e34 idle issues

[hartge h26]

Looking For Help..........

I Have A 91 535i With Electronic Throttle. When I Start The Car It Will Idle Smooth For A Little ( 2-3 Minutes) Then Out Of Nowhere It Will Start Reving By Itself Form 100-2500 Rpm's When Ever It Feels Like. The Eml Light Is On And When I Put It In Drive The Car Wants To Leap Fwd As The RPMs Just To 3k Every Couple Of Seconds. The Car Will Drive But There Is No Power At All. After Approx 1/4 Mile At Best The Asc Light Comes On And The Gas Pedal Goes Dead And The Car Eventually Comes To A Stop.

When The Car Is At Idle And Free Reving On It's Own The Guy Who Owned The Car Before Use The Wack The Throttle Body And The Car Would Go Back To A Smooth Idle For A Bit( Guess He's No Mechanic). I Changed The Throttle Body Control Motor But The Car Still Does The Same.

Any Help Would Be Appreciated.

[hartge h26]

nobody????

[ThoreauHD]

That would be a couple of things. MAF, ICV, and/or fuel filters. This is assuming you don't have a vacuum leak. The MAF is expensive, and the ICV is kinda pricey. I would get a bimmer mechanic to diagnose it, because if you don't know then it'll cost twice as much.

[Ferret]

That would be a couple of things. MAF, ICV, and/or fuel filters. This is assuming you don't have a vacuum leak. The MAF is expensive, and the ICV is kinda pricey. I would get a bimmer mechanic to diagnose it, because if you don't know then it'll cost twice as much.

This sounds like a massive vaccuum leak - check all your hoses around for tightness and cracks. I bet the ASC/ETC is bombing out because it cant cope with the surging idle rpms.

While it's surging like this, unplug your MAF/AFM and see if it stops doing it immediately.

[Ross]

M30 with wacky idle surges..... idle control valve.