Engine Surge with A/C running
 

Hello,

My 2004 4.4i had recently developed the engine surge with the AC running and the surge is pretty obvious while stopped at a traffic light or in a very slow traffic. If I turn the AC off, the surging is gone.

Just called my SA at chapman BMW and he said it could be because of the bad fuel. I always use Shell premium (91).

FYI, I had the transmission software update done some time in last year.

Has any one else has seen this behaviour?

Thanks

Sounds like your IAC. Idle air control valve.

Car at the dealership now. SA suspects it could be because of carbon buildup in the engine as well. Will let me know by this afternoon. Thanks for your reply Big "J".

This usually is the IAC motor, which actually is carbon buildup in the motor itself. I have had luck with removing and thoroughly cleaning it out and ensuring it isn't sticking anymore. IAC motors can also act as a vacuum leak if they stick open. But hopefully you have some kind of warranty so whatever it is will be covered!