By on February 20, 2013

Eric writes:

My question is for Sanjeev Mehta. I purchased a 2010 4 cylinder automatic Toyota Camry LE new and have been using it as my daily driver since. My commute is almost all city driving, so I noticed a quirk about the car right away.

During deceleration, the transmission seems to starve the engine almost to stalling, followed by a downshift and repeated until a stop is reached. This makes for a very jerky process for people like me that like to lightly brake for longer distances before stopping. I asked the dealership about it, they told me it was normal and it will go away after ”learning” my driving habits. Two years later, it still is around. From cruising the web and Edmunds, it seems all of the Camrys with the 6 speed auto suffer from this problem. My question is, why does this happen, why on earth would Toyota put this in their cars, and why has every professional review I’ve read of the car not highlight this problem? Is there anything I can do to alleviate this persistent problem? I had the dealership apply a TSB Toyota released for this issue a year ago, but it has not helped at all.

Sanjeev answers:

Do other TTAC writers have the same common/uncommon name mix up problem too?  What say you, Jake Baruth, Stephan Lang and Derrick Kriendler? But, I know, I know…not everything is about me. So let’s do this thang.

After a bit of Googling, perhaps your dealer applied T-SB-0287-10:

“To improve the shifting performance and smoothness during acceleration, the Engine Control Module (ECM, SAE term: Powertrain Control Module/PCM) and Transaxle Control Module (TCM) calibration has been revised.”

But this link points to something more relevant, and interesting. Many (all?) electronically fuel injected vehicles cut fuel to the engine when “extended braking” in this manner.  They’ve done it since the dawn of EEC-IV fuel injection on my super-precious Ford Fox bodies, that’s for sure.  But ye olde Foxes (5.0V8, 4-speed auto) don’t bog very much at all as they slow down to idle. So what’s the problem?

When you slow down through 6 forward gears, the motor bogs down far more often than older vehicles with only 3 or 4 cogs to swap.  When you combine this EFI program with the lack of low-end torque in modern engines (relative to the low revving engines from yesteryear) and the torque converter’s stall speed (and the computer programming added to it) you have a recipe for a boggy, clumsy downshift. In these “extended braking” situations, that is.

Simply(?) put, there are computer programs designed for maximum fuel efficiency, too many downshifting gears, computer controlled spinning fans (torque converter) and a relative lack of balls in rev-happy modern engines to ensure smooth downshifting. You’re gonna have to live with it.

Or change the way you brake.  Or get a Lincoln Town Car stick shift.

 

Send your queries to sajeev@thetruthaboutcars.com. Spare no details and ask for a speedy resolution if you’re in a hurry.

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54 Comments on “Piston Slap: The Fuel Hating Tranny...”


  • avatar
    Robstar

    I figure on a good auto you shouldn’t feel it shifting around. It should do it smoothly. On the other hand I can ALWAYS tell when my wife’s Kia Sorento (2011, V6) downshifts when rolling/braking slowly to a stop, as I can feel the gear change & it pulls me forward. It is really unnerving & annoying & makes me hate driving it.

    Yet another reason to row your own…

  • avatar
    lowsodium

    This is what you get in new automatics these days. They shift so much you never even get to the powerband. I had the same experience driving a Ford Focus, stupid car shifts through every single gear before it hits 45mph. Show the automakers your displeasure and order a manual next time.

    • 0 avatar
      thesparrow

      I’d like to blame a small portion of this on auto journalists who constantly harp on the manufacturers to increase the number of gears in their auto transmissions, otherwise they are accused of using “old tech” or being “behind the times”. There are plenty of terrific driving cars with 4 and 5 speed auto trannies. Honda in particular has gotten better mileage out of vehicles with 5 gears than others have gotten with 6 or more. Not to mention that we don’t yet know what the long term durability will be of these newer ones with 6,7,8 and so on.

  • avatar
    dsilva

    What about shifting into Neutral, coasting and braking to a stop, then shifting back to Drive when you want to go again? Would this damage the transmission?

    • 0 avatar
      redliner

      Someone correct me if I’m wrong, but I think shifting into neutral reduces wear on the transmission clutches, and keeps the transmission fluid temp lower during heavy stop and go driving because the engine isn’t fighting the brakes at every stop.

    • 0 avatar
      corntrollio

      That’s not a good idea. Slamming the car into Drive again each time when you stop is rougher on the drivetrain than just leaving it in Drive.

      Also, I’d prefer to be in gear most of the time for various reasons. Coasting in neutral uses more gas than coasting in gear because of what Sajeev said — fuel injected engines do not use gas when there is no load.

  • avatar
    Bib

    I just shift into neutral and let the car coast to a stop.

  • avatar
    johnny ro

    I hear the new Mazda tranny is really a fine thing. Waiting for diesel.

    I walk into BMW dealer in Boston maybe 6 years ago.
    -I want to drive a used 3 for around 24k. Must be manual. I will be paying cash. I am cross shopping A4.
    -OK here is an X3
    -Its not a manual.
    -OK here is a coupe
    -Its not a manual.

    Stares at me for a while with his PC screen between us.
    -Whats the matter with you? Why do you want a stick shift? This is the real world.
    -I like to be able to control the engine.
    -Well there are no used 3 series manuals within 75 miles according to the database.
    -OK I will see how this 328x feels. Lets go.

    It lurches my head forward when I let off gas. Feels like active braking but its the engine doing that. It either accelerates or deccelerates, no mid point unless you can find that magic spot on the pedal or use cruise.

    His boss comes by
    -So how do you like the car?
    _its sort of OK except for the way it drives.
    -Excellent. So the monthly is X and here is where you sign.
    -No thanks. I think I am heading over to Audi now.
    -What can I say that will put you in that car today?
    -show me a manual.
    -c’mom, sign here (gives sales guy a mental smack upside the head)

    Magna Powertrain 3 series program manager:
    -Yes, BMWs do do this. That car was not broken, its defective by design. They wanted it this way. Yes it sucks. People in the states don’t seem to care. I would not drive one without the manual. Newer cars don’t supposedly use less gas while coasting, the engine shuts down the injectors when you feel the automatic braking, but they are on when coasting with a manual.

    I bought an A4 5mt for $7k less.

    Ny next Audi with 6mt snaps my head forward in cruise, when I tip down hill and speed up with gravity. No coasting there. I have to remember to disengage the cruise.

    Dealer:
    -No we do not have a software fix. Its for your safety sir. If you want to coast which is illegal you have to disengage the cruise.

    • 0 avatar
      Robstar

      @johnny ro>

      “It lurches my head forward when I let off gas. Feels like active braking but its the engine doing that.”

      THIS IS EXACTLY HOW MY WIFES SORENTO FEELS WHEN LETTING OFF THE GAS. (Sorry for caps but got excited…)

      Thank you for “verbalizing” what I couldn’t. This drives me _nuts_. My wife doesn’t seem to mind….

    • 0 avatar
      Roberto Esponja

      “It lurches my head forward when I let off gas. Feels like active braking but its the engine doing that. It either accelerates or deccelerates, no mid point unless you can find that magic spot on the pedal or use cruise. ”

      Exactly the same thing my wife’s wretched ML550 does. Must be a “German engineering” thing. I hate driving it…

    • 0 avatar
      rpn453

      Are you sure it’s just the engine? I’m surprised there would be much engine braking available in top gear. My buddy has a B8 S4 that actually applies the brakes when going downhill in cruise, or immediately after you let off the gas when passing someone with the cruise enabled. I’d have disabled the vehicle’s ability to apply the brakes after the first time such a thing happened. What a terrible feeling to have a vehicle apply the brakes when you don’t want it to.

  • avatar
    Jeff Waingrow

    It is funny what does and doesn’t get mentioned in car reviews. I don’t recall ever hearing about this lurching problem when reading Camry reviews. On the other hand, I have often heard about lurching from DSG equipped VWs. With my TDI, I’d say that’s the most minor of problems, if even that. But here is an actual “problem” I never hear about: the diesel takes foever to warm up in the winter. So you drive the first ten minutes with no heat other than what you get from the seat heaters. I love the car, but in a cold clime, this is a pretty big negative, especially if you make numerous short runs. Anyone else bothered by this?

    • 0 avatar
      kvndoom

      I refuse to call this “good advice” but when I had my 2004 Gold TDI, what I would do on cold mornings is start it and put the AC on full blast COLD air. A diesel won’t warm up without a load on the engine, and there wasn’t any other way. After 10 minutes I’d jump in, start driving (to continue keeping a load on the engine) and switch the thermostat to heat. Typically I’d have heat for the whole drive (~25 minutes from apartment to work parking lot). On REALLY cold days, I could literally see the temp gauge dropping as I sat at stoplights.

      …the other option is getting an engine block heater installed.

    • 0 avatar
      993cc

      Many Tdi owners are bothered by this. Check out http://www.tdiclub.com.
      The problem is a result of the inherent efficiency of diesel engines- they just don’t make much excess heat that needs to be bled off through the radiator (or heater core). Some owners block off the entire grille. Some use frostheaters. I just live with it.

      • 0 avatar
        Tosh

        I’m calling shenanigans. VW has set up the diesel version to make the engine warm up quicker (and thus lets less coolant into the heater core, and likely leaving more for heating the gel-prone diesel fuel) because it reduces pollutants and makes the car drive better sooner. No heat for you!

    • 0 avatar
      brettc

      The Common rail “Clean diesel” TDIs are supposed to have an auxiliary air heater in them. I discovered this recently from a post on the TDI forums. With my old TDIs, I would just turn the fan off if the engine was cold unless I needed to defrost the front window and would only turn the fan on after the temperature needle had moved some. The auxiliary heater will give you warm air fairly quickly if you crank the heat to max and put the fan on 2 or 3. Then when the engine actually gets up to operating temperature, you’ll be getting engine heat. Apparently if the auxiliary heater dies, it’s an $800 part. So there’s that.

      And the DSG does have some lurching problems. I’m not a huge fan of that part. Aside from that, it’s a nice transmission. But I do enjoy being able to text, eat my McBreakfast(tm) and wack it while driving without thinking about the complicated issue of choosing a gear and actually paying attention to the other multi-ton projectiles around me. (Just kidding, I don’t text while driving!)

    • 0 avatar
      Remi

      My BMW diesel has an auxiliary electric heater which turns on right away – it’s lovely. The engine does take a while to heat but it’s harder to tell…

    • 0 avatar
      mnm4ever

      The DSG lurching is the off-the-line acceleration, or it will happen at low speeds if you try to suddenly accelerate. Makes sense really when you think about it, the trans is trying to be “smart”, and senses that you are driving slowly.

      Now what the OP (and many other commenters) is describing is the opposite: coasting or very lightly braking at deceleration. I have never noticed this at all with my DSG, and the past couple of months I have been trying VERY hard to hypermile and see what I can get the gas mileage up to. I coast any time possible, I light brake at any light, attempting to never come to full stop. Sometimes I will notice a little bit of engine drag which will slow the car a tiny bit but it is never jerky or lurching, nothing you would really notice. Ditto with my CRV, my last Explorer, any rental car I have had, I simply never noticed this as an issue at all.

    • 0 avatar
      mypoint02

      When I was looking at TDIs I read about the cold climate / heat issue and read that VW addressed this by putting electric heaters in the MKV Jetta and Golf TDIs. IIRC, the heat had to be turned up all the way for it to turn on. I’d be interested to see if they carried this over to the Americanized Passat TDIs.

  • avatar
    mike1dog

    I’ve noticed the fuel injection shut off on My 2012 Mustang. I don’t know if it’s as extreme on other cars, but it’s disconcerting to coast down a long semi-steep hill and have the car actually slow down when the fuel is cut off to the injectors.

  • avatar

    FYI: I didn’t notice this problem when I had a 2007 Camry LE press car…but it was a 5-speed auto back then.

    FYI again: on second thought, I bet the power band in today’s engines are only one of the problems. The other is compression ratios (higher than 10+ years ago) and the effect that has on engine braking.

  • avatar
    ToyotaSlave

    I believe Toyota used mostly the same requirement for previous gen Camry. I owned an automatic 4 cyl. 2007 Camry and it does the same thing. 2 things that bothers me a lot:
    1. Downhill braking – as I brake and the car slowed down, the car downshifted, therefore, the car feels like rolling again – start braking like mad! It turned out that as I brake, engine brake is also in action, so when it downshifted – car rolls again. Never experienced that in old automatics
    2. On a slight downhill slope, if I decided to just coast (not pressing the gas), there is a certain engine RPM where it decided to downshift, then after a second, it upshifted because the speed. This roly poly trans can go on as long as I hit that sweet spot between the low RPM and the particular speed
    and no car reviews mentioned this (unless I was blinded by my loyalty to the brand). Test drive showed only no.1 that I mentioned.
    Potential buyer – test the braking on a downhill to a stop to get no.1
    Coast the car on a slight downhill around 45-50 KMH (not sure what the MPH) to get no.2

  • avatar
    jpolicke

    It’s illegal to coast? Where?

    • 0 avatar
      redav

      Most states that I am aware of prohibit coasting downhill with the transmission out of gear. I know of no state that prohibits coasting (including a car moving when the transmission is not in gear) in any other situation.

    • 0 avatar
      cdotson

      I know it’s illegal to coast in neutral in Virginia and likely in many other states as well. This likely comes from antiquated notions of vehicle control, irrational bias toward extremely slow speeds, and the presence of steep grades in the western part of the state.

      The problem of engine braking on pedal lift is exacerbated by modern automatics’ tendency to force torque converter lockup early and maintain it in almost all gears on coasting. This makes each ratio change much sharper and more detectable and increases the braking torque transmitted to the wheels. Stall speed is irrelevant of the converter’s in lockup mode.

      I too strongly favor manuals. It may be for that reason that I dislike automatics that shift too smoothly. An undetectable shift means parts are wearing each other out, while a neck-snapping shift is getting the job done. If you want something that smooth, buy a CVT.

  • avatar
    JLGOLDEN

    Let’s talk about my WORST transmission experiences EVER: Volkswagen’s latest DSG crap-box. I had DSG in a 2010 GTI and a 2012 Jetta TDI. In ordinary stop and go driving, or when coasting in traffic, parking lots, etc. the DSG would bog the engines down and lurch into lower gears. The DSGs “clacked and popped” and shuddered under light throttle under 35 mph. All normal. No PCM reflashes made a difference. This was all deemed to be normal per dealers and various VW forum commenters. Horrid and sloppy and disconcerting to me and passengers.

    • 0 avatar
      dts187

      I love the DSG in my 2012 GTI. Shifts quickly, shifts are well-timed, and flappy paddles are fun for back road heroics.

    • 0 avatar
      brettc

      Did you get two lemon DSGs? Mine does some lurching at low speeds (particularly when braking) but I’ve gotten used to it so it’s not as surprising now. No lurching happens when I go to manual mode.

      I’ve read of people getting the mechatronic unit replaced and having that solve some problems. DSG is a good concept, but I think they could do some additional work to smooth it out a bit more. But most drivers are morons and probably don’t notice so VW probably doesn’t care too much about it.

      • 0 avatar
        JLGOLDEN

        I urged the VW service department to consider utilizing intelligence derived from internet buzz, blogs, reported solutions, etc. for learning how to tackle my vehicle’s concerns, but without a “trouble code” and some sort of magical corporate blessing (or complete vehicle break-down) they only performed some electronic update, which was useless. I think the abrupt engine-braking nature of the DSG is simply incompatible with my city driving. If I drove the cars agressively, the DSG’s hiccups were less obvious. Driven mildly, in normal conditions, the lurching and related pop noises (parking lots brought out the loudest demons) resulted in a couple of passengers saying “WTF is wrong with your car???!!” and a co-worker passerby, in the parking gargage, thinking that I was driving a manual tranny, stuck in 1st or 2nd gear…as engine braking with attempted gentle coasting was too dramatic.

      • 0 avatar
        mnm4ever

        I think you had to have gotten lucky (?) and had two bad DSGs. I can’t even make my car behave that badly, even in Sport mode, at low speeds. Even if I just stick it in 1st and try to make it jerk it simply doesn’t react that fast to slow-speed throttle inputs. The worst thing it will do is if I am pulling out from say a side street at slowish speeds, then immediately floor it to merge into traffic, transitions like that will sometimes cause it to buck or jerk the car as it tries to correct for the change in shift direction, but I couldn’t safely do that in a parking lot. I have learned to drop it into Sport or manual mode in those situations and then it doesn’t have that problem.

        Typical VW though… some people get great ones that work fine, others get dramatic problems.

    • 0 avatar
      mnm4ever

      Have to disagree, my 2008 GTI with DSG has none of those issues. Never any noises, no clacking or popping. It was a bit jerky when I first got it but the mechatronics unit was recalled early on and since then it has been fine. As I posted earlier, it will lurch a bit off the line when I try to accelerate hard, you have to sort of ease into it, once under way if my foot is to the floor it bangs off every shift without any jerkiness at all. When I try to hypermile the shits are imperceptible. As long as I give the automated clutch time to engage when starting off, I get no lurching at all. When decelerating I cannot tell it downshifts at all, coasting is fine too unless you are trying to go really super slow, then you can sort of feel the clutch engage but I have the same problem in my manual MR2, you can’t go THAT slow without slipping the clutch. I can “creep” just like a regular auto without any jerkiness.

      Now if I put the DSG in Sport mode, it is not so smooth, especially at deceleration. The upshifts are clearly being felt, it holds revs longer even at light acceleration loads which can feel jerky. It rev-matches at decel, and you feel it downshift each time, basically the DSG seems to drive the car like a stereotypical punk GTI driver would. :) But it isn’t lurching, it is just “spirited” and lots of fun. My only real complaint with the DSG is that it is a bit boring compared to a real manual, and there is always that dread deep down that someday something really expensive is going to break. No way would I call it “horrid”, even my wife says it drives exactly like a regular automatic.

      Unless you were constantly driving the car with the gear selector in S, and then trying to drive it sedately, I think you just had a bad mech-unit and a bad dealer who wouldn’t fix it.

  • avatar
    redav

    Obviously, an automatic coasting will have more resistance (engine braking) than a transmission in neutral. That’s expected. However, what is described doesn’t match well with what I recall seeing, but I haven’t been specifically thinking about such a thing.

    I am no transmission expert, but it seems the issue is not with the number of gears, but the transmission trying to stay in gear, or the problem could be in the engine instead of the transmission.
    - Some newer ATs are more agressive about locking into gears to improve efficiency. If it doesn’t let go when slowing, then it could stall the engine just like a MT.
    - Newer cars are more aggressive about shutting off fuel injectors to save gas when coasting. They rely on the transmission turning the engine to keep it going. Even if the engine slows below idle, you wouldn’t notice until fuel goes back into the engine to get its speed back up. If the computer waits too long to restart the fuel system, then it could certainly stall.

  • avatar
    Bimmer

    That’s how Toyota punishes you for misspelling Sajeev!

  • avatar
    toplessFC3Sman

    It seems like the torque converter(TC) lock-up clutch (TCC) is really the culprit here. Older automatics only rarely used the TCC, and only in the higher gears. When decelerating, the clutch was open (so power would go through the TC’s fluid coupling) for smoothness, and the engine still had fueling (at least in lower gears where it could drive the trans, but not the other way around) so it wouldn’t stall. More modern transmissions use larger TCC’s more aggressively, and on deceleration tend to use them now to keep the engine spinning instead of letting essentially “idle”, saving that fuel, but potentially making the experience when they shift less smooth.

    When the shift happens under deceleration, either the TCC needs to open, or it can stay closed. If it is opened during a shift, then the fueling needs to turn on to keep the engine running and help (along with the TCC closing) to drag it up to the new speed, using fuel when its not really necessary, and turning it off when the new gear is fully engaged. If the TCC stays locked during the shift, then the engine is forced up in speed very quickly as the transmission input speed increases with the downshift. No fuel is used this way, but it can be jerkier (depending on how smoothly the first scenario’s TCC open-closed and fuelling transition is handled).

    Add to this the greater number of gears (so higher frequency of shifting), greater compression ratio (more engine braking), and lower number of larger torque impulses (fewer cyls result in more powerful, less frequent pulses – or a heavier flywheel/flexplate that needs more energy to accelerate), this can start to become a problem

    • 0 avatar
      KrisZ

      That’s what I’ve been thinking as well. Pretty much all fuel injected cars have fuel shut off and it was never a problem until manufacturers started playing with TCC lockup in various gears, where before TCC was only engaged in top gear.
      In essence manufacturers are trying to mimic a manual tranny and clutch setup with poor results to improve fuel economy.

    • 0 avatar
      Onus

      I honestly would like to drive a car that does this. My complaint with old automatics is they don’t downshift unless your going like 5mph, and they engage the coast clutch as soon as you let off the gas. It doesn’t let you use the engine to brake.

  • avatar
    number9ine

    “Lightly brake for longer distances”

    …which accomplishes nothing except just as much wear on the brake pads over time plus glazing of the friction surface, not to mention uneven application of the pad surface to the rotor, which is the ultimate cause of the “warped rotor” falsehood (hint: the rotors aren’t warped, the brake pads are bedded incorrectly). I can thank you and others like you for the stuttering stops in every rental car I drive.

    Try this: Use half the distance you normally do to brake. Apply the pedal initially with progressive firmness, then soften at your stop point. Your Camry will thank you.

    • 0 avatar
      redav

      Or rather, just coast without using the brakes.

    • 0 avatar
      nvdw

      I’d like to add a +1 on that.

      I drive buses for a living and if you thought your AT was ill-mannered, which it probably is, you haven’t seen anything. By braking progressively harder instead of just ‘dragging’ on the brakes you’d not only save your brakes but also iron out most of the downshifts. If it’s slowing down slowly that you want, just let it coast instead.

  • avatar
    Zackman

    I wonder if this is more of an issue with smaller cars, or a combination of all the above that has been discussed?

    Wifey’s 2002 CR-V has good engine/tranny braking – sometimes too much – when going downhill without lurching, but my Impalas – both the old 2004, which I sold, and my 2012 LOVE to roll!

    The downshifts in the Imp are almost imperceptable, but the thing is fairly heavy, so perhaps it’s a combination of factors.

    I’ve only driven a Camry once in my life, back in 1996, a rental, but noticed nothing out of the ordinary, but that was a long time ago and the world has considerably changed since then!

  • avatar
    deliverator

    I have a 2008 Civic Si. 6-speed manual. Is it bad to engine-brake often? When coming to a stop, I plan ahead and am off the gas earlier than everyone around me, who accelerates to their stops. But I usually leave it in gear, say 4th, and push clutch in and go into neutral when the rpm’s go down to about 1500.

    Is this bad for the engine bearings, for example? I thought I read that somewhere once. Now that I know those laws about not coasting in neutral on level ground are not really applicable to today’s cars, I woulnd’t mind going into neutral much earlier.

    If I need to cancel the stop, I’m pretty good with matching the revs correctly and going smoothly into 2nd to accelerate again.

    • 0 avatar
      redmondjp

      What you are doing is perfectly fine! No need to worry about engine damage. I drive my 5-speed Civic the same way, but I let the engine speed drop to 1K rpm before depressing the clutch.

      • 0 avatar
        mnm4ever

        I don’t think engine braking your Civic will damage anything, as long as you aren’t downshifting as you get to the stopping point. Each downshift will add some clutch wear, which is OK, but clutch replacements are expensive too, so putting it off as long as possible is good.

        But I wonder if simply letting off the gas and engine braking in top gear will waste fuel compared to just slipping the car in neutral right away and coasting/light braking to the stopping point?

        I have been having a little contest with my wife over who can get the best gas mileage in my car. We have a long shallow hill by our house, and I have compared the mileage when simply coasting down the hill in gear, compared to putting the car in neutral over the same stretch and coasting at idle RPM. I definitely gain 1-2mpg in my average when I neutral coast vs in gear coast. Now this is far from scientific; I have a DSG not a real manual, I am using my fuel economy average display, the hill is only at the end of our trips, etc. But so far I have gotten myself up to 26-27mpg over short trips around town (though my wife still beats me with a consistent 28-29mpg over the same basic area!) This is vastly better than the 22-23mpg I see when I drive the car like I used to.

      • 0 avatar
        SN123

        Engine braking uses less gas than idling. Idling is about 14:1 air-fuel ratio, engine braking a lot leaner. Takes fuel to keep the pistons moving up and down at 1000rpm or whatever whilst idling. Doesn’t take fuel to make them move up and down when the wheels and car slowing is doing it for you.

        So it’s more economical to coast to a stop in gear than slip it into neutral in a normal engine. DSG, couldn’t say how that acts, might be different from what you’re saying.

      • 0 avatar
        mnm4ever

        That makes sense, thanks for the explanation. This morning I tried the hill again just to see. It is not a very steep hill (this is FL afterall) so I think the problem is I cannot “coast” in gear and maintain the 35mph speed limit without giving the car a little bit of gas. If I let it coast down to 30mph or so, the DSG downshifts, slowing the car even faster (Perhaps this is the situation described in the OP’s question?).

        So I am running around 1500rpm or so to make it to the end. If I slip it in neutral, then the car will coast at 35-30mph all the way down, idling at 800rpm or so. So that is probably why I see a little bump in my avg then… combination of the way the DSG works and the lack of slope in FL.

      • 0 avatar
        redav

        mnm4ever, over at one of the Focus boards, they experimented with your situation, and they found that the Focus gets better mileage by leaving it in gear than putting it in neutral. I found with my own, older car that it gets better mileage in neutral than in gear.

        It all depends on how aggressive the fuel shut off is and how much internal resistance the engine has, and probably other factors, too. There won’t be a single right answer.

    • 0 avatar
      corntrollio

      “Is this bad for the engine bearings, for example?”

      No. Lugging is bad for the engine bearings under load, but that’s not what you’re doing here. If you tried to accelerate hard in 4th gear at 700 rpm, then you might lug the engine and do something bad to your bearings, but deceleration isn’t a problem here.

      What you’re doing is quite fuel efficient — modern cars use less fuel coasting above idle than they do at idle, generally, because the fuel injectors don’t inject fuel when there’s no load.

  • avatar
    tbhride

    I wonder why Sanjeev Metha’s knickers are in such a twist. Anyone know?

  • avatar
    tbone33

    The problem with torque converters is that they rob horsepower/MPGs and aren’t crisp in their shifts, problems that multi-clutch automatics remedy. The problem with multi-clutch transmissions is that they don’t offer the smoothness that torque converters provide. As is often the case with new technology we have gone from one extreme to the other.

    Mazda presently has the best solution in their SkyActiv transmission, as they have married a multi-clutch tranny with a torque converter that is only used at low speed. Eventually someone will develop a more elegant solution with fewer moving parts. Then we’ll have something 90% as good as a manual.

  • avatar
    Cabriolet

    Jeff Waingrom Your TDI has a built in electric heater. Just turn the temp dial to full heat and the electric heater will be turned on. Diesel,s take a long time to warm up if possable drive in a lower gear to keep the engine speed up or install an engine heater. Works great on cold days. Have a DSG transmission in my 2011 GTI and i love it. Only way i know it is shifting is to look at the tech. Slowing up for a red light is very smooth. If you have any trouble in up shifting or down shifting contact your VW dealer. They have some TSB’s to cover that. I always drove a stick shift all my life but i can not shift as fast as the DSG. And the best part is i get better gas mileage with the DSG then driving a stick. Enjoy


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