idle bouncing

[oldskool3]

Hey guys when I started my car today the idle kept bouncing constantly between ~1000 and 1500 rpms. Any ideas?

[Eric Giles]

Hey guys when I started my car today the idle kept bouncing constantly between ~1000 and 1500 rpms. Any ideas?

More than likely the idle control valve needs to be cleaned or just replaced.

[dupemaster]

I have the same problem. After cleaning what I think is the idle control valve and replacing my mass air sensor. I still have the problem, it's a bit smoother, bit still there. Can someone take a picture of an ICV. My manual is fairly vague about it. Maybe my search foo is bad, but I cant find it here either.

I had it a a mechanic to try and figure it out. He told me it could be the coolant temp sensor as well. I don't know. I'm not that mechanical. (body work--- Cool. Engine---not cool)

[submwar]

Circled in red.

[Garageaholic]

vacuum leak

[mact]

there are several temperature sensors that directly affect the idle. one increases idle speed until coolant reaches XX degrees, the other shoots extra fuel in until coolant reaches yy degrees. Nope...don't recall what xx and yy are<G>

So it is true that a temp sensor can cause this issue.

the Bentley manual (at least for my 84 325e) covers using a voltmeter to test these sensors.

vacuum leak is also a good likelihood. close eyeball inspection...any cracks, split hose, anything loose and can be wiggles when it shouldn't be? I had "visual but couldn't go thru the rubber" cracks on one hose that I didn't think could possibly...yup. wrongo! wrapped the hose with radiator repair tape and it fixed the funny idle.

[dupemaster]

I have checked, double and triple checked all of the hoses. No leaks. I have also found receipts in the glove box from last year, all hoses, plugs, and plug wires are less than a year old.

It mostly only has these idle issues until the engine is warm (after a good ten minuets of warm up) After that, is smooths out, most of the time. I'll put a volt meter on the temp sensors and check them out. If that's not the problem, I don't know what to do next... Any one know a GOOD mechanic in the Seattle area?