By on June 4, 2012
Nate writes:

Hi Sajeev,

You asked for some emails, so here’s one from me. It may not be Piston Slap worthy, but it’s got me confused. Here’s my problem:

I have a 1998 Nissan Frontier. 150k miles, 2.4l four banger. It threw a Service Engine light on me the other day. The code is a P0301, i.e. cylinder #1 misfire. Figuring it was a spark plug issue, and since I was about due for a tune up anyway, I replace the plugs, wires, distributor cap and rotor. I cleared the code with my scanner, and….it came right back. I did a little creeping on the Nissan forums, and the consensus seems to be that this results from clogged EGR passages. So this past weekend I decided to clean them. I was lead to believe that this would be a cake walk. All that was required was to remove the set screws between the intake runners, spray some carb cleaner in there and scrub them out. Easier said than done. Removing the screws was not too bad, but putting them back in after cleaning was nigh impossible. 5 hours and sawed off 8mm Allen wrench later, I had the plugs back in. My truck ran great! For 20 minutes. Then the code came back. Now I’m pretty much flummoxed. The way I see it, my options are:

1. Remove the air cleaner assembly and manifold screws again and try cleaning them more thoroughly with a pipe brush and more carb cleaner
2. Try something like Seafoam through a vacuum hose. I am reluctant to do this as I’m not 100% sure which hose to use and opinions on Seafoam are mixed
3. Take my vehicle to a mechanic for a more professional diagnosis. I do have access to a reputable independent mechanic who specializes in Nissans and Toyotas

So, what do the B&B think? Anyone else had this problem with a Nissan KA24DE 4 cylinder?

Thanks for your help.

Sajeev Answers:

Looking at the picture above makes me long for the days when we had an assortment of small pickups in these United States, but we all know these older rigs will never die. And here’s proof.

All three of your options are valid, the armchair quarterback in every TTAC reader can’t argue with that.  In my experience with the dreaded cylinder misfire code is that a multitude of wear items are at fault.  What truly matters in this case is the truck’s mileage both on the odometer and at the gas station.

If your oxygen sensors have over 100,000 miles on them, replace immediately.  And don’t skimp, get a brand name like Bosch or the factory Nissan stuff. If nothing changes and you also feel like fuel economy isn’t optimal (only you know your driving style, etc) for your commute, then maybe even a bad fuel injector is to blame.

My point is that many items are behind this problem.  Which truly sucks, especially if you have multiple trouble codes present.  My recommendation?

1. If you have ANY doubts about your previous work, remove EGR and clean passages with everything from a screwdriver to toothbrushes with plenty of carb cleaner. And wear gloves, for sure.

2. Replace oxygen sensors, both of them.That’s part of a complete tune up. Ditto the PCV valve.

3. Grab a piece of new rubber vacuum line and note its physical properties.  Then replace every hose under the hood that is too soft, too hard, too glazed, or anything else. Since you aren’t afraid to get your hands dirty, just spend $15 for new hoses and replace them all.

4. Seafoam through the PCV valve (probably the ideal place) if so desired.  We all know the pitfalls with Seafoam, but I will admit that it’s worked for me on several occasions.

If all of this fails, get to your mechanic and tell him all the hard work you did.  Best of luck…not that you need it. I suspect you are almost done.

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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21 Comments on “Piston Slap: There’s a Misfire on the Frontier!...”


  • avatar
    GS650G

    Sometimes it’s important to look at how the computer detects the problem, and in this case why it is focusing on one cylinder not all of them.
    I would look at a bad o ring on an injector causing a leanout on that cylinder, a bad intake gasket (or intake o ring), and finally don’t discount the possibility of bad connections, you can sometimes do a wiggle test where the computer will look for questionable readings while you move wires around.
    It depends on the computer and what options are available.

  • avatar
    Zackman

    Hmmm…you seem to have done almost everything you could. Follow Sajeev’s advice and if that doesn’t work, it’s time to take it somewhere and hope it isn’t the engine itself, for that opens a whole new door of “opportunity” – a rebuild or a new engine or a junkyard rescue out of another Frontier.

    Maybe shoulda bought a Ranger to begin with, as I know nothing about Nissans?

  • avatar

    My old Protege once dropped a screw from the intake runners into the combustion chamber. The first symptom was a misfire code. When I pulled the plug, the electrode had been smashed flat!

    I also once owned a MR2 Spyder, which are known for sucking bits of catalytic converter back into the engine and ruining piston rings.

    Just in case you wanted to worry about other potential reasons for a misfire code.

  • avatar
    olddavid

    How about water? It worked as a last resort on my car which I thought was wrist pin failure, but obviously was carbon deposits as the sound is gone now, and running smoothly once again.

  • avatar
    TR4

    Before throwing more parts at it why not do a compression test?

  • avatar
    Halftruth

    I wouldn’t change a thing more (yet). I would try a reseat of # 1′s injector connector first. Check it for corrosion as well. I have seen many a misfire code from dirty injector connections. I believe you can ohm it out (do both warm and cold) and be sure they are in spec. As it ran good for 20 min, it could be a temp related issue on the injector OR on the parts you put in!!! Never trust new parts when the same issue repeats!! I have learned this one well over the years.. Good luck.

  • avatar
    noxioux

    You should throw a search on the http://www.nissan4wheelers.com forum. Maybe register and try the question out there. It’s been my go-to Nissan site for ages.

  • avatar
    poltergeist

    O2 sensors should have no effect on a cyl misfire. I’d suspect a tight valve(s). Has the valve clearance ever been inspected?

    Can you sense that the #1 cyl is misfiring? You can pull each plug wire one at a time with the engine idling. No change with that wire removed means the cyl is weak or dead.

    You should be able to disable the EGR by unplugging it if it’s electric, or pinching off the hose if it’s vacuum controlled. If the misfire goes away you know it’s EGR related.

    If they’re not too hard to access, you can swap fuel injectors from one cylinder to another and see if the indicated misfire moves with the injector.

  • avatar
    noxioux

    You should throw a search on the http://www.nissan4wheelers.com forum. Maybe register and try the question out there. It’s been my go-to Nissan site for ages.

    You didn’t say how that #1 plug looked when you pulled it. If the plug was normal, you could just be chasing gremlins.

  • avatar
    I_Like_Pie

    If you do the seafoam…do it BEFORE you swap out the oxygen sensors.

  • avatar
    Nate

    Thanks for the help so far, guys. I hadn’t considered an O2 sensor. I’ve done a perfunctory check on the injectors with a stethoscope, so I’m fairly confident the injector on cylinder 1 is at least functioning. I attempted to remove the EGR valve for cleaning and inspection, but it is STUCK.

    I should also mention that the EGR ports are extremely dirty. Even after a round of cleaning and Seafoam they are still very full of carbon. Unfortunately they are very hard to get to without removing the throttle body. I did manage to clean out the back port after loosening the EGR valve. I discovered a rifle bore cleaning kit works fairly well.

    So, I’m going to reconnect the EGR valve, attempt to clean the other three ports more thoroughly and see if that works. If it does, I’ll probably go ahead and replace the O2 sensors as Sajeev suggested and keep on trucking. If not, I’ll give my mechanic a call and let him sort it out. Thanks again for the help. Even though this is a second vehicle for me, as I’m sure Sajeev can tell you a single cab pickup with a 5-speed can be a fun little daily driver.

  • avatar
    Felix Hoenikker

    I had a vexing problem with P0301 for over two years in a 3.0L Taurus Vulcan V6.
    Following the diagnostic charts in the manual led me to the #1 spark plug that had a thick deposit on it. None of the other ones did. Turned out it was a small coolant leak in the #1 cylinder. Exhaust gases were also in the coolant. I tried to seal it with a can of Monroso head lead stopped but no dice.
    The presence of etylene glycol in the exhaust gases tricks the oxgen sensor into reading a high oxygen concentration. OBDII inteperets a high O2 concentration upsteam of the cat convertter as a misfire.
    A local mechanic diagnosed the leak as a failed head gasket, but he was wrong. Turned out the leak was coming through the top of the head itself.
    I ended up replacing the head with a rebuilt one from Advance Auto. The car runs like new now, and I haven’t seen the check engine light since.

  • avatar
    redmondjp

    As mentioned above, a coolant leak could also cause this code – has the coolant level remained steady?

    The fuel injector could be dirty or plugged, and that can’t be detected by electrical testing or by listening for clicking sounds. An easy way to scan for this issue is to check secondary ignition voltages, as an abnormally low or high voltage indicates problems. A high voltage can indicate a lean mixture, which can be caused by a malfunctioning injector and/or a vacuum leak.

    At 150K miles, it wouldn’t be a bad idea to pull all four injectors and send them out to the local injector test/repair house (in our area there is one guy called either “Dr. Injector” or “Mr. Injector” that does this for all of the repair shops) for inspection, cleaning and repair. Make sure to mark or bag them with the cylinder numbers and ask for a detailed report.

    A cylinder leakdown test would also be in order, just to verify the basic engine mechanicals. Carboned-up intake valves could be causing the problem as well.

  • avatar
    p4nya

    Drive her hard til she gives up the ghost, then SR20DET swap.

  • avatar
    Sinistermisterman

    Excuse my lack of knowledge, but as Seafoam isn’t sold in the UK, I’d never heard of it until I moved over here. What exactly does it do and how does it work? I’ve watched a couple of demonstration vids on youtube which quite frankly scared the bejeezus out of me. That much white smoke blowing out of your exhaust is never a good thing in my book!

    • 0 avatar
      redmondjp

      It’s essentially a solvent that one can add to the oil to clean out crankcase deposits, add to the fuel to clean out injectors and intake valves/ports, or (as I suspect the videos you are referring to show) directly into the intake manifold in order to clean out the intake path and combustion chambers.

      It can be compared to the old shade-tree mechanic’s trick of dribbling water down the carburetor (often from a Coke bottle) in order to clean out the carbon in the combustion chambers.

      There is copius information on using this product available on dozens of discussion forums. Use at your own risk, your mileage may vary (YMMV), and so on . . .

    • 0 avatar
      TR4

      @ Sinistermisterman, compare to REDeX engine treatment in U.K. I think the clouds of smoke are part of the attraction; boy, look at that smoke it must be doing something!

      • 0 avatar
        Sinistermisterman

        Redex has got to be the stupidest thing I know of (to those who don’t know, you tip the bottle into your fuel system). It’s ‘supposed’ to clean your engine… Does it b*llocks. A mate of mine decided to go down that route. All he ended up doing was dislodging a decades worth of crud from his fuel lines and bunging the injectors up. His £5.99 fuel treatment cost him 4 new injectors. Woo!

  • avatar
    MBella

    I would bet some money on the #1 injector. I bet you swap it out and you will be fine.

  • avatar
    greaseyknight

    Check out a guy on Youtube with the username “Scannerdanner”. He teaches diagnosis at a tech school, and is an amazing teacher.

    If you scanner supports it, I would check the misfire counter, this will tell you when the misfire is occurring. Also check the fuel trim numbers to see if the truck is running rich or lean. To check the injectors, you should do an injector balance test, that checks to see how well they are flowing, not just that they are working.

    My understanding of an egr system is that activates at cruise, hence if the misfire occurs at idle, the egr shouldn’t be the problem (just guessing). Have you tested that the egr is working (usually activating it at idle)? Also check for bad wiring, it can cause some interesting intermittent problems.


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