Piston Slap: Coked Up and Stumbling in Dearborn

Sajeev Mehta
by Sajeev Mehta

Confused1096 writes:

I have a 2001 Ford Windstar LX that is slowly driving me (and two mechanics) crazy. I have an intermittent issue with hard starting and rough idle on initial start up. The problem will clear up after the van has been running about 4 or 5 minutes. There are no codes in the computer’s memory. I’ve been chasing this for a month now with no luck.

The van has 76,000 miles; it is equipped with the 3.8L V6 and a 4-speed automatic. Other than this issue it has ran great since I bought it three years ago. The battery is new, recent tune up, fuel filter, IAC valve, PCV valve, and coolant sensor. This thing has been babied since purchase (I’m a regular here, after all). Any suggestions would be appreciated.

It knows I’m car shopping. Could it simply be jealous?

Sajeev responds:

I have three guesses.

Guess one: the Windstar is totally pissed at you. Ford products can do that, especially if you use them to run around town reviewing cars for TTAC. Believe that.

My second, more intelligent, guess: cracked vacuum lines on the EGR system, intake manifold and air box duct work. Often the pre-bent hoses crack and leak, checking them is easy/free. Replacing them isn’t much worse: you might replace the pre-bent parts with plastic “T” fittings and universal vacuum line. Both are dirt cheap at the local parts store if you get a person behind the counter who knows their inventory. There should be a box of Gates-branded fittings for this need at any parts place.

Third, most likely, guess: the EGR system isn’t operating properly. This could be a bad valve, a coked-up intake manifold (around the EGR port or the individual intake runners) or maybe a problem with the vacuum lines. With (somewhat) low miles and a low revving engine in this case, my money is on the coke deposits.

I’d take a look at the intake with the EGR connection removed, or better yet, SeaFoam the living daylights out of that van. You should Google “SeaFoam smokescreen” if you don’t know what I’m talking about. Keep your foot to the floor and grab a gas mask.

Mike writes:

My ’02 Ford Explorer stumbles a bit and stalls sometimes at intersections. The local repair shop finds no codes pending or real, and can’t make a guess why.

Sajeev replies:

Hey Mike, I can guess why: your Explorer’s been talking to someone’s Windstar.

Seriously, do a tune-up if it’s getting close to that time: replace the plugs, fuel filter, PCV, etc. as stated in the owner’s manual. Also check out the vacuum line information presented above. Consider Seafoam (cheap) or some sort of intake de-coking too. If it still stalls, the IAC valve (somewhat expensive) is suspect: it can crap out and not throw a code.

And if that fails, there is some EGR problem (mentioned above) that de-coking didn’t resolve.

[Send your technical car conundrums to sajeev.mehta@thetruthaboutcars.com]

[As someone who has SeaFoamed his engine, my advice is do it in a sparsely-populated area away from traffic as the profuse white smoke creates a drving hazard.—Jeff P.]
Sajeev Mehta
Sajeev Mehta

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  • Confused1096 Confused1096 on Mar 20, 2009

    Sajeev: Not a problem. I'm thinking of taking this thing to the local autocross group, just for the laughs.

  • Jgh Jgh on Mar 20, 2009

    RE: the Explorer: It could be several different problems, but one interesting culprit that caused this on my '95 was a failing 2nd gear shift band in the 4R55E transmission. Combined with an about-to-go torque converter, the engine would begin to stall at rolling stops as it would not appropriately downshift into 1st gear and the TC would not adequately take up the slack. Since the 5R55E is fundamentally the same trans used in 98+ Explorers, it may be something to consider. How many miles, and what engine/trans is it?

  • Lorenzo Heh. The major powers, military or economic, set up these regulators for the smaller countries - the big guys do what they want, and always have. Are the Chinese that unaware?
  • Lorenzo The original 4-Runner, by its very name, promised something different in the future. What happened?
  • Lorenzo At my age, excitement is dangerous. one thing to note: the older models being displayed are more stylish than their current versions, and the old Subaru Forester looks more utilitarian than the current version. I thought the annual model change was dead.
  • Lorenzo Well, it was never an off-roader, much less a military vehicle, so let the people with too much money play make believe.
  • EBFlex The best gift would have been a huge bonfire of all the fak mustangs in inventory and shutting down the factory that makes them.Heck, nobody would even have to risk life and limb starting the fire, just park em close together and wait for the super environmentally friendly EV fire to commence.
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