Car runs great cold, but when it gets warmed up it has a miss under 3500 rpms. The car has great power and pulls hard at wot but any other time it misses. Just replaced plugs, wires, opti, and intake gaskets. I tried runnung fuel system cleaner through it but it didn't help. Any suggestions?

 

Sounds like a closed loop issue, check 02 sensors...maybe change the coil.

 

I was wondering if you have found what your problem was. My car is doing the same thing and the only thing that I have found was that the wires are arcing and they are all new,three sets of plug wires,2 optis, 3sets of plugs,2 ICM's,new coil and still the same issue. It stumbles really bad when sitting still and loading up the converter. Can't figure it out.

 

the o2's were replaced 500 miles ago, they are the delco's. Also changed the maf last summer so I think thats ok. The #7 plug is the one that fouls out so I'm gonna try swithching the inj onto another cylinder and see if the problem carries over to that one.