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      07-06-2009, 01:25 PM   #20

Drives: 06 BMW 330i
Join Date: Jul 2005
Location: Los Angeles, CA

iTrader: (0)

Originally Posted by clairvoyant View Post
check for vacuum leaks first ... clean the MAF, and IAC valve, check/replace airfilter....

as said before, it COULD be the beginnings of VANOS seals failure ... you can unplug the intake side vanos solenoid and if the problem stops, then that is likely your cause...

do you have any cold startup idle issues?
thanks for your insight.

no cold startup issues. with the ac off, the idle is rock solid at around 600 rpm. with the ac on (and it gets worse with the fan speed turned higher, i.e. worse at with max a/c) the car occassionally jolts and i can see the rpms bounce up by a couple hundred rpm when idling at a traffic light.

i understand that it's normal to feel a slight vibration and see a slightly higher rpm with the AC on, but what i'm experiencing is a very obvious shake that occurs intermittently.