no more idle RPM

After starting my car and letting it warm up, my rpm needle is moving up and down. but when you start driving, everything is fine. then once you stop at a light, the needle starts to move up and down again. if
you don't do anything it will eventually die out. what do i need to do? what causes that problem?
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Its a vacuum leak. Check the rubber hoses and the intake boot for cracks. Its a common problem that's usually pretty easy to fix. My old e30 325i and e36 M3 both had these symptoms with a badly cracked intake boot.
Kyle. 98 740iL 01 525i
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Babee Q wrote:

Babee - perhaps some clue as to WHAT model and WHAT year BMW is causing the problem might be useful. BMW has been making cars for over 70 years so there is a wide selection that might have the problem.
Dog helps those who help..
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admin wrote:

i have a 2000 BMW 328i....i had written a message one before this which is why i didnt include this info in this msg. thanks and sorry
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I had that problem many times (635,735,318,535,540) and it always been a "sticky" idle regulating valve. First check connection and if everything is fine try to clean it with brake cleaner spray. On your engine it's not an easy part to reach, it is underneath the intake manifold.
good luck

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