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Eratic engine speed

Printed From: - BMW Owners Discussion Forum
Category: Technical & Model Specific Forums
Forum Name: BMW 6 Series
Forum Discription: This forum will deal with any issues on the BMW 6 Series (E24, E63 & E64)
Printed Date: 22-February-2020 at 01:12

Topic: Eratic engine speed
Posted By: Howard
Subject: Eratic engine speed
Date Posted: 24-March-2014 at 14:38
My 635 has started revving up from 1500 revs to 2500 and back down again, making it almost un-driveable except in 2nd and with a foot poised on the brake.
Changing the startup temperature sensor had some effect, but it was only short term. Now it revs between 2000 and 2500 RPM.
Has anyone else had a similar problem, and if so how did they solve it.

1963 700 LS
1988 635 CSi
1990 M635 CSi no longer!
2001 E38 728i Individual" rel="nofollow -

Posted By: Andrew Rolland
Date Posted: 24-March-2014 at 15:23
Idle control valve bunged up?
Clean it out with Wynns Carb and fuel injector cleaner, dissovles oily gunk in seconds.
I had an erratic idle problem on my Mini, turned out to be the ignition coil.
Air leak from egr system or inlet manifold joints etc.

Be exclusive and drive a Petrol 5 Series!

'13 62 F10 535i MSport Auto

'04 04 E60 545i SE Auto
'03 53 E60 545i SE Auto (Stolen)
'98 S E39 523i SE Auto

Posted By: Indian
Date Posted: 25-March-2014 at 09:20
I had similar problem with my E23.
Recon AFM and change all the vacuum and intake hoses solved the problem.
Starts on the button even after sitting in the garage for 2 1/2 months

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