Weird idle problem

Highlander179 · 01-04-2005, 07:00 PM

my 95 325i with 156k miles has this weird occurrance lately. I've noticed that my idle has been a little higher than normal lately (1000-1200rpms) and I've been getting this weird surging/revving on decel. When coming to a rolling stop, with the clutch in, it seems the throttle is blipping several times. It will blip up to about 1500rpms about two or three times until I come to a complete stop. Then it just settles at a high idle again. Any ideas?

Jared at Pelican Parts · 01-05-2005, 07:01 AM

vacuum leak somewhere most likely.. Also check your idle control valve and see if the slide is sticking at all...

Highlander179 · 01-05-2005, 07:14 AM

OK, so I'm a total newb mechanic. Lets start with the vacuum leak. How many different places do I need to go looking and where are they? I guess I need a manual or something.

kocio67 · 01-05-2005, 07:26 AM

Check this out...

blkongry · 01-05-2005, 07:31 AM

Try running some fuel injector cleaner. My '94 325ic was doing a little of the same at times... just kind of a weird surge of the idle like it was trying to compensate for something... I put in some injector cleaner and it's been running smooth ever since. My guess was that at low RPM the injectors may have been a little clogged and were having a hard time getting the right amount of fuel in, therefore the computer was trying to compensate for the sporadic injector spray, hence the idle surge, especially on deceleration or after accelerating.

If it were a vacuum leak, you would get the problem constantly... it wouldn't be the weird 'blipping' of the throttle. If you have the same thing I had, you can tell the computer is trying to compensate for something... it's almost like the car is confused for a second or two, but then gets it right.