just built the tranny and put it back in a 94 Lt1 A4. the car ran awesome for about a half an hour then it started missing and when you pressed the gas it would fall on its face. blows black smoke and fouls the plugs. also the pass side manifold gets hotter than the drivers side. cat was also just replaced

so far its thrown 4 codes:
-IAT sensor too low temp(23)
-MAF circuit(48)
-EGR circuit (disconnected vacuum line - fixed)(32)
-ICM circuit/grounding(42)

Ive replaced the ICM, and gone as far as taking the MSD dist off and it looks healthy for being on there since march. the MAF, IAT, and ICM all share the same ground but i cant find it.. could a bad ground connection be the problem?

 

It sounds like something came loose or was off and it took sometime to show up. The ground wire is on the front drivers side head.