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?

 

same problem here, i changed everything you said and fuel filter, fuel pressure regulater, egr, waterpump, coil, map sensor, pcv valve, vacuum lines, iat sensor. the only thing left for me to replace would be fuel injectors, maf sensor and icm...so im thinking its one of them. i am going to run some test to find out tomorrow

 

If it only happens when its warmed up, first thing that comes to mind is an o2 sensor. Itll stumble and fall all over itself with an o2 sensor shot. And i didnt see it on your list of replaces.
You throwing a code, or did you throw a code? Have it scanned.

 

forgot about that, i did replace those....with bosch. i heard they are not the best though.

 

check that coil wire.

 

I've had nothing but a terrible time with Bosche's... :/ They would be first on my list to swap out for some ACDelco's...

 

well i just did that test when you unplug them, nothing happend, still ran like poo

 

I replaced my o2's about 500 miles ago. I tried the bosch and had to go back to the delco's. I put a new maf sensor on last summer so i'm pretty sure thats ok. I put on the new coil wire that came with the plug wires. The only other thing I can think if is injectors, the #7 plug is the one thats fouling out so I'll try moving that inj and see what happenes.

 

okay i just got my car scanned and it turned out to be 3 codes:
23_ which is manifold air temp too low. it was -44,so it came down to the iat bad unit and damaged wire
16_ low revolution pulse failure, and that was corrosion on the connector for distributer
77_ fan 1 fault...i was aware of that, my fans dont work automatically so i wired manual fan switch