Simon1

Ever think your cold tranny might cause the issue?

Or, maybe need a good tranny flush? A convertor can cause the engine to feel like it's missing or surging.

mtgldr

Good suggestion except the Fluid & Filter were changed within 2000 miles. It started when I changed all the things listed above. Didn't do it until then...

Simon1

What exactly did you change all at one time?

If you did CAI, tune, CMDP and UDPs all at one time, I would look at metered air getting in or out first, which it seems you have already done. This is anything within the intake system. But most likely it needs a tune adjustment. The computer in these cars are very sensitive to just one thing being slightly off. The tuner is applying a known tune to a mechanical machine, assuming everything would be the same with the other machine the tune was made on.

I've seen this happen many times before. Especially when cold weather sets in. The canned tunes are generally really good, but they do not account for all temps. That's one of the reasons custom tunes generally are better. Just consider it. Maybe call whomever did the tune and explain it occurred after the install.

mtgldr

CAI was already done, car did not stumble. I had a tune done for the CMDP and have done several data logs since then. I have been back to the tuning Co's quite a bit over the past 2 months. I got so frustrated with the first one I paid for tunes from a second co. The stumble still exists. I sprayed intake cleaner all over everything, have checked for air leaks and can find nothing. The odd this is it's only until the temp guage on the car begins to move then it's fine. I have datalogged till I'm sick of datalogging. Had I known what a PITA it was going to be to buy tunes this way I would have gone to a shop in the first place.... Even before I did the CMDP the first Co never got the tune right and all I had then was a CAI. The second Co has the car running well overall but the stumble still exists. Don't know if the TPS can cause a stumble or not. To me it would need to be injector or spark related. Thanks for your repley

Simon1

When you say "stumble", does it sound like it's missing? Sort of like the engine is running normal and then it sounds like a hollow sounding echo? it might sound and look weird, but mine, after being tuned with the built motor and turbo, would idle great, but sounded kind rum,rum,rum,rum,rum,rum,rum, blah, rum,rum,rum,rum,,blah, blah. Sort of like a miss, erratic, mostly when it's cold.

That's the dumbest looking sentence I have ever typed.

bjbrowder

No its not the trans, because mine I's a manual and it does the same skip when the engine is cold. Also, its not the TPS because mine did it with the stock TB, and now does it with the Ford Racing TB.

mtgldr

Dang... there goes that idea.... Wish I had a bad TPS I could disassemble or a known good one. Just for the heck of it..

mtgldr

close... more like a rum, rum, rum, rum, blurp, hick, rum, rum, rum, rum, blurp, hick, rum

Simon1

Its not abnormal for a tuned car to do that. idk....Seems like you've checked everything.

And blurp is more descriptive. Thank you.

gregthomas07gt

I bought mine with the cai and tune already installed. It ran perfect and then 20000 miles later it started. So I don't think it's the tune. Mine does it when it's hot too. 1st gear lunges in parking lots, stumbling at low rpms, feels like the a.c. is kicking on and off while accelerating, just generally a rough acceleration, hesitation and lurching but not rhythmic like a dead miss. The best way I can describe it is like driving an older car with a sticky throttle cable. A battery cable pull clears it up for a few hundred miles then it slowly comes back. I've cleaned and sealed and tested til I'm blue in the face. Changed anything and everything and spent money on parts that didn't fix it. And we are not alone. Do a Google search for S197 hesitation... hundreds off forum posts and most are left unanswered.