PontiacBonnevilleClub.com

Hey guy's help me get this car fixed. Ever sense replacing engine earlier this year, it has run sluggish above 50mph. Below 50 you cant ask for a better running car. Only CEL it has is from not having cat anymore, but it ran the same way then also. It's been tuned up, ICM changed, new crank sensor, MAP, fuel pressure reg and so on. Could the PCM be causing engine to run bad? Also the transmission seem's to want to shift way too soon. I have a TPS I can try in the morning. Please help me save my car from trade-in.

did you try you mass air flow sensor?

Tried the spare I have, no change. Unplugged the TPS but tranny quit shifting so plugged back in. Will try spare TPS to see if that helps. When engine was changed out, dealer didn't mess with PCM wonder if maybe they should have.

CASE learn for the new engine, maybe?

Try cleaning the MAF sensor, and make sure the intake air temp. sensor is working.

The engine does need some backpressure to get torque. This occurs in low-RPM situations such as on the highway. At 50 mph the engine is turning ~1300 RPM, IIRC. So running without a cat could be having a deleterious effect.

If you were going for fuel mileage, people would kill to have their transmissions shift sooner!

If my PCM does need a case learn, how do I do this?

Anyone with an HPTuners or a tech II can do case learn to my knowledge. Probably other programs will work, but I don't know what all else. The stealership can rip you off, unless you can get them to do it for free. The process takes a minute at best.

TPS helps control the shift timing.


Did the transmission get replaced when the engine was replaced?

No new tranny when I made the swap. Got a gut feeling I might need a case learn. Will call around for best price.