My car was revving itself slightly during idle and I also noticed this when coming to a stop at red lights now and again. I read up and apparently I needed to clean the ICV. There was a usefull DIY from a UK bimmer board, but I felt it simplified things a little too much and I thought I would share my experience...

This was done on a '95 325is with an M50TU engine and CAI. It worked for me but don't blame me if you screw something up...

First of all.... we're working under the hood from above:

We are going to be concentrating on the intake area of the engine:

You're going to take off the air duct that feeds the alternator:

Now you'll undo your CAI:

Next you will undo your MAF:

Now place the MAF off to the side:

Next you remove the rubber elbow from the Throttle Body:

The ICV has 2 hoses running from it. The first one connects to the rubber elbow. You're going to simply pull/twist it off:

Now you can remove the rubber elbow and put it out of the way:
(dirty throttle body... ewww)

Before you start trying to take the ICV out, you should understand what it looks like. The hose on the right is the one you just unplugged from the rubber intake boot. The one on the left runs verticl and into the underside of the intake manifold:

Here is the ICV as it lays in your engine. The white circle is the bottom of the ICV and it runs as a cylinder towards the passenger compartment. Notice that I have highlighted the hose that you just unplugged from the rubber boot:

This is a look below the intake manifold showing the 2nd hose running from the ICV which plugs into the intake manifold. Note that you undo it where I have circled and I had to soak it with WD-40 and gently use a flathead screwdriver from above to work it loose. I pointed out the ICV position:

You'll have to unplug the electical source to the ICV. There is a metal clip on the bottom side that you push up while pulling the plug towards the front of the car:

Note that there is a rubber circle that holds the ICV tightly in place. You will need to push the ICV towards the rear of the car to slide it out of the grip of this rubber piece. The rectangle I drew running diagonaly to the right is a metal piece that the ICV sits above. Notice I highlighted a tube running parallel and to the right of the ICV. That normally sits above the metal piece but I moved it below to access the ICV better:

Here is the ICV pushed away from you and about to fully clear the rubber piece that holds it:

Now comes the hard part! To get the ICV out of there you need to basically have it follow the path of the tube that ran to the rubber intake boot. You will have to go slow, moving the ICV and hoses in different angles as it is tight. I didn't think I was going to get it... but it came out with patience and some force.

To clean the ICV, you just dip some Q-Tips in rubbing alcohal and wipe out everything you can see. Then you pour a bit of rubbing alcohal into the ICV, shake around and drain. Once it's all dry, spray some WD-40 and re-install!

Here are pics of the two sides of the ICV. Mine was originally all black inside:

Isn't it a good idea to clean throttle body "while you're there"? Is it hard to disconnect it ( TB ) and leave it connected to coolant hoses only and clean it that way (basicly while it's still under the hood)? How would you do it...by spraying some TB cleaner (teflon safe) in and out and wiping it off...orrrr, some other way?! Thanks...

Okay so I did everything the write up said and now my engine revs are unstable and the engine shakes quite a bit, instead of what it was doing. (rpms dropping to 400ish when i came off the throttle) I have checked and rechecked my work, whats up? O2 sensor next?