Car runs fine at idle and WOT, only under partial throttle and light load does it surge/slip/buck/misfire. No computer codes. Dealer said transmission was slipping and replaced it and computer (ECU) - same problem. Replaced plugs, wires, dist. cap and rotor, ignition coil and oxygen sensor - same problem. Been to several diagnostic shops - no answers. What are the odds of a new transmission having the exact same problems as the old transmission? I'm beginning to think maybe the dealer charged me for a new transmission but didn't install it. Any ideas?

 

Has anyone checked the EGR system?
It is possible the torque converter is causing the problem, but that usually ONLY occurs during lock-up apply...not once the converter is fully applied, and not under steady driving conditions.

The description sounds more like an EGR problem to me. Or possibly a vacuum leak somewhere. The transmission cannot cause a misfire.