Piston Slap: Coked Up and Stumbling in Dearborn

Sajeev Mehta
by Sajeev Mehta
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]

[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.]
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2 of 33 comments
  • 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?

  • FreedMike I don't know why this dash shocks anyone - the whole "touchscreen uber alles" thing is pure Tesla.
  • ToolGuy CXXVIII comments?!?
  • ToolGuy I did truck things with my truck this past week, twenty-odd miles from home (farther than usual). Recall that the interior bed space of my (modified) truck is 98" x 74". On the ride home yesterday the bed carried a 20 foot extension ladder (10 feet long, flagged 14 inches past the rear bumper), two other ladders, a smallish air compressor, a largish shop vac, three large bins, some materials, some scrap, and a slew of tool cases/bags. It was pretty full, is what I'm saying.The range of the Cybertruck would have been just fine. Nothing I carried had any substantial weight to it, in truck terms. The frunk would have been extremely useful (lock the tool cases there, out of the way of the Bed Stuff, away from prying eyes and grasping fingers -- you say I can charge my cordless tools there? bonus). Stainless steel plus no paint is a plus.Apparently the Cybertruck bed will be 78" long (but over 96" with the tailgate folded down) and 60-65" wide. And then Tesla promises "100 cubic feet of exterior, lockable storage — including the under-bed, frunk and sail pillars." Underbed storage requires the bed to be clear of other stuff, but bottom line everything would have fit, especially when we consider the second row of seats (tools and some materials out of the weather).Some days I was hauling mostly air on one leg of the trip. There were several store runs involved, some for 8-foot stock. One day I bummed a ride in a Roush Mustang. Three separate times other drivers tried to run into my truck (stainless steel panels, yes please). The fuel savings would be large enough for me to notice and to care.TL;DR: This truck would work for me, as a truck. Sample size = 1.
  • Art Vandelay Dodge should bring this back. They could sell it as the classic classic classic model
  • Surferjoe Still have a 2013 RDX, naturally aspirated V6, just can't get behind a 4 banger turbo.Also gloriously absent, ESS, lane departure warnings, etc.