Idle control valve issues
 

For the first time ever my 88 325is let us down. Kind of. My sweety was driving it and all the sudden it would not stay idling. Code scanner said idle control valve. Tested it, the ICV, and it was good. So I figured wire connection or the computer. I ended up replacing the computer and the code cleared as well I noticed a significant difference in the idle. However... Where as before if I disconnected the connection to the ICV before it would cause the engine to stall out. Now there is no difference at all in the idle performance when I disconnect the power to the ICV. There is no rich smell in the exaust or anything. Is there something I am missing or does anyone have any idea as to what is going on here? Thanks.

I'm not driving it right now anyway so I can't give a real update. The timing belt is due and I need to install new shocks. So the pony is in the stall for now. I have taken it out a few times though and the idle is slightly up and down... Very slightly, and intervals between 5 to 10 seconds just ever so slightly up and down. Noticeable though. And one more thing I hate to admit. Before I replaced the computer, and against my better judgement. I adjusted the screw at the throttle body because I noticed the stop on the throttle body was not touching the factory set idle screw. The throttle cable and cruise control cable were really loose too. So I adjusted those as well to the Bentley specs. I did however move the idle screw back to what I think is exactly where it was set before. I hope I didn't mess up because I love driving this car. And damn these TV show hackers. FLAG EM!!!

Sounds like an intake air leak to me. I had a similar issue with my 88, and it turned out to be the butterfly was not closing all the way in the throttle body. It had deposits on it and was allowing air past. also check the rubber intake elbow for cracks.

I was thinking about an air leak on the elbow (or in that area) myself. I had a similar issue & found a crack in the bellows on the underside. Buy the better bellows if you replace it; the cheaper ones didn't last long & I ended up replacing it again, this time from Pelican!