BMW: 84 bmw running rough, cylinder cars, rubber boot

Question
Well Josh it's me again ,I really appreciate your help in finding out the problem with my son's car. before I recieved your last message I was checking other possible cause's for the high idle(3000 rpms and when driven for a very short time 35000 rpms at idle) and I wanted to know if you think that it could be the idle air stabilizer. It doesnt seem to adjust at all and one of the things when I had it in my local shop was the iac was bad(but they told me not to worry about it) this was the first time the car gave me headache's. Is this the same thing as the idle air stabilizer? the shop just want's me to bring it back in (of course) for the price of 379.00 for parts.      any ideas or suggestions.. I have checked everything else out so far and no luck.    Thank you very much for your help so far     Tom

Answer
Tom
 Yes, the Idle control valve, Idle air control, Idle control stabilizer... they are all the same thing.  Its a little valve that is controlled by the ECU and lets air bypass the throttle body to smooth out the idle.  I'm not sure where it would be located, but on my 6-cylinder cars it is on the rubber boot coming from the AFM to the throttle body.  It is about 2" diameter and 4-5" long.  It has a cable that plugs in to it.   If you find it, you can remove it and spray it out with carb/choke cleaner or some starting fluid.  That should clean it out if it is faulty.  if it still doesn't work, it probably is bad and needs to be replaced.  I dont think I would take it to the shop unless you had to, seems like you are doing fine as it is.

 Like I said in the previous email, I think a 3500 idle is a little high for the ICV (idle control valve) to be acting up.  Although I may be wrong about it, I've just never seen an Idle that high from a bad ICV.

 Let me know if I can help anymore.
 Thanks,
 Josh