Piston Slap: Coked Up and Stumbling in Dearborn

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]