i have two words for u guys

OXYGEN SENSORS

check them or replace them. i had the same problem and ruled everything out except for them. if u r sputting and missfiring when u warm up(not cold), that means that u are in closed loop(car is running off of the 02's, compared to open loop not listining to the 02's) and the 02's are a very good possibility

 

i was going to change mine while installing the headers, but was too impatient!

 

I can't speak for the thread originator as I haven't seen a scan of his car, but I can safely say that it's NOT my problem as it takes less than a minute of run time after a cold start for my symptoms to appear. The fastest I've ever had the car jump to closed loop (strictly idling only) is about 3 minutes.

 

I'd put my money on the opti

 

i sometimes think it is the opti too, but it used to do this two years ago, then all of a sudden stopped. who knows??!!!

 

Im having the smae problems.... however it starts to shake, stumble, and backfire around 2200rpms under load...and even without load it will still stumble. I'm going to swap my o2s out and report what happens.

-B

 

Please do, i'd love to hear the results! but,
My quess is that the range of adjustment via the o2 sensors is narrow enough that even if unplugged or pegged out in one direction that it would not make the motor run that bad, only an opti failure. Unplug the MAF, it will run in open loop only, and run, just as bad. The o2's are only used in closed loop. I drove my car for 2 years in open loop, 94z with headers 13.5 @ 108.

 

ttt