Ok, I just got my car back yesterday from having a new water pump and optispark installed. The car still stumbles at launch and still won't shift at WOT! What could possibly be wrong? I'm trying to sell the car soon so I need to know asap, thanks guys.

 

Sounds like tranny related. Maybe someone who knows electronic trannies will step in.

 

This happened to me....and the reason was as simple as I had just installed a new Smooth Below.. If you have aftermarket intake (air lid, below, M.A.F. ect) then try and reconnect / re-tighten everything.

A lot of the time the problem is caused by a misreading of air coming into your car by your CPU.

Try that, and if not then Gluck anyway.

 

The tranny has already been checked out/flushed I was told it was fine. The next logical step for me to take was the opti (since it was acting goofy anyways). The car has a stock intake setup, would a cleaned-out or new MAF possibly help?

 

Doubtful it would be that the MAF just started acting up :-/, dunno what other advice to give ya..TTT!

 

describe how it stumbles

 

Ok the car we're talkin' about is actually mine, A-Man930 was just posting for me before. Anyways when i hit the gas from a stop half the time it stumble for 2 seconds like it hesitates or something. Then it will take off like it should. Second when i'm at WOT and i'm nearing the shift point it will start making this horrible popping/banging noise, which sounds to me like back pressure in the exhaust. It starts this around 4800-4900 on my tach. My Redline is 5250 if i remember right, which i would assume is where my rev. limiter would be set. Could i have a bad factory tune?, maybe my rev. limiter was set to low? I don't know, but any help in this matter would be profoundly appreciated! Thanks A-Man930.

 

Bad map? Bad O2's?

 

this is a manual right? are you turning off the traction control system that my be way it stumbles at take off now the red line the factory tach on most f-bodys don`t keep up with the rev of the motor they can be a little slow so if you are at 4900 rpm the motor may be at 5200-5300 rpm so don`t be worried to much go get a hypertech system and you can turn it up if you feels so

 

No sorry i didn't specify, it's actually an A4. So what you suggested, will it still apply? Sorry rather new to detailed motor talk, so please excuse my ignorance. And my car doesn't have a traction control button. It actually has a "transmission perform" button that stiffens the shifts.

 

well untill you can get the engine to pull cleanly to 5,800 (stock LT1 red line) it won't shift. The reason is it is programed to reach a certian RPM and MPH. If it does not reach either of those it will not shift

BTW the MAF could be an Issue but not like on a LSx based car.

Also when was the last time you changed the Fuel filter More then once I have had clogged fuel filters keep a car from revving

 

That seems like a quick and cheap fix i will try that first, but keep the suggestions coming. I will keep you all up to date on the progress of this issue. again thanx guys.

 

Any more suggestions guys?

 

i still need help, please.

 

So you changed the fuel filter?

 

Faulty TPS sensor, did they even plug it in?

 

We're changing the fuel filter today, we'll keep ya posted, wish us luck!

 

On a 94 aren't shift points only based on MPH? There's a few global values that are rpm related but there's no rpm shift table like for MPH.

worst. advice. evar.

 

94-95 code is near Identical and can be swapped back and forth in the same PCM.

Yes there are RPM flagg's also. You can make the code shift off of RPM if you wanted to. The Code in my PCM is modified to do just that and completely ignore the MPH flagg's

I think more then any thing he needs to get the car running correctly

 

We changed the fuel filter last night (a messy pain in the butt!) and it did nothing. So next step in the fuel-related area would be the injectors I guess. Has anyone experienced results from sonic cleaning the stock injectors? And with the whole MPH vs RPM issue, what are you guys suggesting we do? The car only recently started doing this, and we haven't messed with the ECM at all. We still haven't checked the TPS though, how would we test for a faulty one?