[blownsnake]

Ok guys, here is the issue and what I have done so far.

Here are the syptoms. The car starts idles rough for a sec(open loop), smooths out and runs perfectly(closed loop) until the car reaches operating temp or close to it (gauge reads about 200-it stays rock steady at that temp), it does this consistantly each time it starts. Once it gets to op temp, it runs rough, like the timing is being retarded by the eec.

the car is a cobra replica, the engine (1990 5.0 with 9al), all sensors etc are new, no smog. The engine pulls a few codes but they are normal codes for a non emission car. The egr has been eliminated, but was done correctly. No codes for anything or condition on the car as it is now. I replaced the coolant temp sensor, the IAC, reset the idle and TPS correctly. I am stumped.

Again, the car runs flawlessly for about 5-10 minutes until it gets to its operating temp and then runs really poorly, it will run, idle etc. but it rough and sounds and smells like its running rich. Any thoughts or suggestions will be appreciated.

[ryans88gt]

Air charge temp sensor? Check for codes.

[Trick Tuners]

Bad O2 sensors? I would stick it in open loop, if i was tuning it, and see if it went away. Do you have a wideband?

[blownsnake]

I have been thinking the o2 sensors might be the culprit, but they are pretty new, (1000 miles).

How do you force the car to run in open loop?