I just got ripped off by my local mechanic seeing as he charged me $368 to change my timing belt on my 86 325. So I am currently having idling problems, and am going to try to cure it myself instead of giving him my other arm as payment. However I need some input.

The car will drive perfect, idle perfect. When I put it in park, the RPM's
will rise to roughly 1300 then fall quickly to about 600....It ONLY does this in park. Any ideas? It really bothers me and I would like to fix it.

Second is the Anti Lock light is on. What exactly does that indicate? Just curious.

Thanks!

In terms of idling, I'm not too sure where to start... when I had an idling problem with my car, I gave it a tune up, spark plugs, wires, ect... but maybe a simple idle adjustment could do it. Not too sure, but hope this helps just a bit. Anti-Lock? Maybe something wrong with your ABS. Definitely not sure about that.

Try cleaning out or replacing your ICV (idle control valve).

For the anti-lock light, check your ABS relay. Had same problem on my old E30, turned out that the relay was burned out. Seems to be common.

Thats the first thing I did was the ICV. Im still stumped. I checled all vacuume hoses. IDK

my car has the same problem. when the engine is cold my rpm moves. my mechanic cleaned the idle valve then it went a way for a day or two then it came back. then he did something and now it only idles two times when the engine is cold. still my engine light comes on!!! I paid $1500 for a engine replacement, now its going to cost me a couple of more benjamins to fix my next problem. -_-

I'm not too familiar w/the 3 series but I ahve been fighting idle issues with my 5er for awhile now. I ahve had the head gaskets replaced, pcv plate, had the fuel return line moved, fuel pressure regulator replaced yada yada. I know my car is known for bad intake gaskets so thats my thought. I am tempted to try some of that liquid gasket to see if that helps form a better seal. The last time I ahd it to my mechanic he hooked up a pressure guage to the fuel return line and the pressure was rather low. Other than that I am waiting till winter to see if I ahve the problem again.

On the '86, in addition to the idle control valve, there's an idle control unit located above/behind the glove box (little green box near the DME). They should just be replaced at the same time, it's so hard to figure out which is the problem.

Well....after stressing over the idle problem i believe i figured out why it was doing what it was doing...

When i took off the ICV to clean, apparently the adjustment came loose or something, so I just screwed it down a little and it brought the idle down to 700 and as of now there is no surging...

Let this be a lesson to all...when you mess with things on the bimmer, make sure you put them back just as you left it, or she wont like it!