My 1998 2.2L Cavalier with 79,000 miles loses power and does not go higher in RPM's while pushing on the gas and takes awhile to build up in speed. I can floor it and I can hear the car trying to build in RPM's but is not able to (Tachometer physically bounces). Sometimes when driving it does it less, but usually stays the same. ONLY DOES IT IN DRIVE. Symptoms do not show in Park, Reverse or Neutral. Also, have tested with break on in reverse and drive. Car falls apart in drive while brake is on, but acts normal in reverse.

I have changed the Spark Plugs and Wires twice, fuel filter, checked the EGR Valve (Removed plug, only change is rough idle), tested IAT Sensor (Strange hard shifting after removing plug from Sensor), changed oil and oil filter and removed catalytic converter (Straight pipe currently).

The last thing I was going to check is the transmission, and I have put a whole bottle of Lucas Oil Transmission Slip Fix and it seemed to help for about 10 minutes, and now it is still doing the same thing. I was thinking it potentially could be the transmission, because the car only does it after it has warmed up and possible that it does it when the transmission fluid gets warm and thinner.

I have thought about replacing the Coil Packs and Ignition Control Module, but these are upwards of around 150$.

ANY IDEA IS A GOOD IDEA. Thanks for your help.

 

check your fuel trim and fuel pressure during a sustained acceration.