Crazy Idle

[PrinceE30]

Yesterday had some weird problems with the car idling.

Driving around downtown Atlanta. At the stop lights the car would idle weird (erratic) for 20 seconds and then idle fine. Then about 30 minutes later the idle was erratic any time I was stopped. Anytime I let off the gas there's some odd engine behavior. Sometimes it even will die when stopped without my foot gassing her a little.

Driving the car is perfect. I can really put the hammer down and shift, downshift, etc without problems or engine erratics.

Sounds like idle control valve, yes? (ECU should be good, I'll know next week when i get my spare from home)

Thanks!

[lowslowe30]

My eta had the same problem basically and it was the afm. Take it off and see if anything is making it hard for the door inside it to open.

[PrinceE30]

Like the actual "door" in the AFM housing was the problem (after the air filter but before the throttle body)?

-Prince

[BMW BMXER]

Adjust/replace ICV

[Kavkazia]

Try cleaning your idle control valve with WD40, and check for any cracks.

[PrinceE30]

Thanks for all the help everyone! I'll check it all out and get back to you tomorrow!

-Prince

[David325is]

I had a similar thing happen to me. I just removed the idle control valve and sprayed it with some carb. cleaner.
The car ran fine after re-installing the valve and leaving the car run for 2 or 3 minutes.

[Streetspec_iS]

O2 sensor maybe.

[PrinceE30]

On my trip up to Tennessee today it fixed itself...thanks for the ideas though. I'll be sure and check that all out if the problem happens again!

-Prince

[BS87]

If its acting up on idle and sometimes dieing, check all the hoses and the intake bellows for vaccum leaks. If your lucky, it will be a cheap hose or the intake bellows which is around 20$. If your not it will be the ICV which is around 130$ from BAVauto, or if your really unfortunate you'll need a new AFM which is anywhere from $340-$500. Glad to hear it fixed itsself though. Usualy if my idle is bad the first thing i do is check for a vaccum leak.

[Erick]

Obviously those prices are from BavAuto and you can get it much cheaper in other places if you look around.

[BS87]

Yeah i know, but Bavauto happened to be open in another window and i did a quick look. The AFM from bimmerparts.com costs around $500 AFAIK.

[modifiede30]

If its acting up on idle and sometimes dieing, check all the hoses and the intake bellows for vaccum leaks. If your lucky, it will be a cheap hose or the intake bellows which is around 20$. If your not it will be the ICV which is around 130$ from BAVauto, or if your really unfortunate you'll need a new AFM which is anywhere from $340-$500. Glad to hear it fixed itsself though. Usualy if my idle is bad the first thing i do is check for a vaccum leak.

You can find almost everyone of the above parts on ebay for less than $50, and if you want, you can upgrade to the m30 afm for about $50 too. Getting these parts new for a 15 year old car is a bit anal if you think about it.

[DaN]

While we are on the topic of AFMs, what is the correct way to test one, and where can the specs be found? Are there any sites that provide such info?
There is a topic I posted earlier in this forum dedicated to this..