[manwer]

This probably isn't a new thread but I'm not finding anything so I might be asking the wrong question. I have an intermittent Check Engine Light on my 328ci. It will illuminate, seemingly randomly, until I park the car for a few hours or a few days. Length of time doesn't seem to matter. When I start it up the light is gone and remains gone for several days or several start-drive-stop-park cycles. Then it can reappear. Anyone have any clues about this?

 

[cyberkaa]

The CEL is supposed to illuminate after 2 consecutive drive cycles when the fault is detected and extinguish after 3 consecutive cycles if the fault is not detected, IIRC. Some failures require more cycles.
It just means you have something on the verge of failing. You'll have to read the codes, which will be stored for 40 or 80 cycles even if the light is out and the fault is not detected.