Quote:
Originally Posted by cmh269
Hoping to revive this thread. I'm having very similar symptoms on my 08 535. I'm really suspecting something to do with the VANOS or possibly O2 sensors for a couple reasons:
1) Problem disappears once oil temp has warmed up.
2) The misfire is so inconsistent. When first starting engine idles at around 1200rpm...no problem. Gradually makes its way down to about 700....no problem. Then for the final drop down to 600rpm, you actually feel a very noticeable shudder and BAM, rough idle at around 600-650rpm. This eventually settles down as the car warms up. If I wait 5 mins (more in the Canadian winter) before driving everything is normal. If I try to drive right away, I feel a loss of power and a lot of studdering, fluttering feel to the engine. The AFR seems ok, so I'm suspecting something to do with VANOS....
Any thoughts?
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Assuming you have MHD
Try adjusting Idle rpm to 700 or 750rpm
I've set mine (335i) to 750rpm and it's smooth as butter at idle.