what causes a miss at idle? cold its pretty smooth, but as soon as i take it down the block and back its missing like crazy at idle.

brand new spark plugs and o2 sensors within the last 3 weeks, new wires, coolant temp sensor, opti, ignition control module (spaced 1/2 inch off head), fuel pump, fuel pressure regulator, !EGR, !AIR, hooker LT's with CAI. i've dissassembled my throttle body to clean it out and put all new gaskets on it a few months ago. BLM's didn't seem split when we scanned them awhile ago, but they were both rather low (115 - 119). ran through a "motorvac" cleaning (similar to seafoam) as well.

seems to come and go... sometimes the thing will idle so smooth so that my radar detector cord doesn't move, but other times its missing so bad you can make mixed drinks in the passenger seat.

doesn't seem to burn oil, no visible anything comming from exhaust. after a fresh PCM reset it ran so rich that it spit out smoke, but that quickly went away when the car warmed up and has never returned.

 

Ive got the same problem here. My miss is intermitent like yours and it runs fine most of the time. I dont think mine is as bad as yours yet though

 

You didnt say anything about the commonly forgotten fuel filter. That can cause all sorts of idling and driveabiltiy probelms. I had a miss at idle that went away with a fuel filter swop.