Idleing Problem on my '99 M3 - Please help

[larry28]

I have just bought an otherwise superb 1993 M3 Convertible. All is working well except for one thing which always occurs when cold and often occurs when warm:

Normal idle speed is around 800rpm. When starting from cold it races to 2000rpm and will take up to 5 minutes to settle down to normal idle speed. It will then do this fluctuation sporadically when warm.

Also, on one occasion only when I put on the air con it went from normal idle to 1500rpm in a sort of rythmn every few minutes...although it only did this once for about 30 minutes and hasn't done it again.

Its depressing me...any advice would be much appreciated. :dunno:

[Robs96M3]

has a cam change been done to it? if so, it could alter the idle. there is a simple fix if this is the case. if not, i'll keep thinking and try to come up with something else.

[bauerhockey66]

Idle control valve? Try giving that a good cleaning.