GPa4

I hate them, now I have a new problem besides the rough idle. Now whenever the AC compressor is off, after a few minutes of driving and the oil temp is about halfway up, when sitting at idle the RPMs drop to about 100-200 and then go back to about 600, no stall though. I cleaned out my ICV about 4 months ago, run injector cleaner twice a month, ran throttle body cleaner last month too. Any clues? I was thinking it might be my MAF?

-Dan W.

AudiMick

IMHO only way to really clean that sucker is to take it off spend some time cleaning it and replace the gasket and vacuum lines. The MAF takes about 20 minutes to clean so its worthwhile. When you cleaned the ICV did you really soak the piston /chamber with gumout. The first time I did it I just sprayed it. It worked for 6 months. The second time I filled the mechanical part with gumout and let it soak for an hour to remove the varnish.If you take the throttle body off check your EGR valve at the same time. A leaky gasket or loose valve will cause this kind of problem.

dorsal900

Based on the advice of AudiMick, I replaced my vacuum lines. The two that connect to the throttle body (9:00 out the passenger side, 4:00 out the drivers side viewing from front of the car IIRC) were in bad shape, but it's very hard to see as they are "buried" in the engine and covered with a woven cloth covering that masks the cracked rubber underneath. They get a lot of heat abuse due to their location. You will have to take off the plenum.

It is probably best to cut off the old hose along its length with a sharp blade rather than take the chance of breaking somthing by pulling on a stuck hose - in particular on the plastic vacuum accumulator "ball" that sits behind the three ignition coils.

I replaced mine with 3.5 mm I.D. silicone hose from HoseTechniques.com as I do not want to repeat going in there for this, but any vacuum hose should work (do not use washer hose - too thin). My car had similar idle problems as yours, this solved it.

GPa4

I will do the vacuum lines when i get some time, then check the egr too when i soak the icv this weekend.

moribundman

My TB was pretty gummed up, and I doubt that spraying from one side would have removed all the varnish.

Also, if you take the TB off you can easily clean out the narrow EGR passage, which is probably restricted or clogged by deposits. Just make sure you have a new TB-to-intake-manifold gasket.

You should also make sure the TB-to-plenum gasket is nice and tight. I found a major vacuum leak there on my engine.

JWG

that's the only way to "kill" those Gremlins causing vacuum system problems.

We have all had to go through this at one time or another--Do not get too frustrated; you have our support.