Car won't idle, backfires when accelerating [Archive] - Bimmerfest - BMW Forums

: Car won't idle, backfires when accelerating

07-13-2010, 03:21 PM
I'm new to the forum, and desperate for help. 2003 745 Li, won't idle, will smooth out at higher rpm, setting still. When picking up speed, it backfires. Have checked for vacuum leak, don't know what else to do. Could it be catalytic converter? Junk blowed out of the exhaust. Don't want to take to dealer if possible.

07-13-2010, 07:45 PM
An indy can fix this... Sounds like a bad cat...

07-14-2010, 07:47 AM
You probably have a bad fuel ratio, more air then gas, could be fuel filter, injectors, mass air or computer/timing, mixture problem, i will start from easiest way, if you use regular jump to super, then change your fuel filter, then computer