When the engine is cold, car runs very well and good power. As soon as engine warms up, engine feels with no power sporadically??!!!!. So I said, simple!, change O2 sensor. SEnsor changed and same!!!. no messages on board, checked sensor electrically ok!!. Erratic only after warms up, temperature sensors seems ok, neddle right in center, no overheating or engine misfiring notice?. this is rare. Any help guys? could it be injectors? why only when warm??. Does the idle valve could cause this after warms up?. or the Air flow sensor? Any suggestions? 735i, 1988