OK, one more try. My car has trouble staying alive in open loop. I start it, it runs for a minute or so, then the rpms start to drop and the car sputters and dies unless I romp the throttle. This continues until the temp reaches around 160 degrees, or, as i have learned, when she starts to run in closed loop. After that it runs like a clock. This started happening shortly after headers and a tune, so for now I am blaming the tune. I can't see how it could be any mechanical problem since it doesn't do it all the time, just when she starts up cold (open loop). I don't know how to do anything but turn wrenches so if somebody wants to give me some advice, please do. I don't like having to sit in the driveway and diddle the throttle for five minutes before I can go anywhere.

 

Check the coolant temp sensor, to make sure its telling the PCM the engine is cold, so the PCM can enrich the cold-start A/F ratio, and elevate the idle RPM.

Also, get it scanned to see if the long term fuel corrections have reached their upper (160) or lower (108) limits. If they have, its using the short term fuel corrections to make further A/F ratio corrections in closed loop, but the short terms are not available in open loop.

 

thanks for the input.