I can't figure out my high idle speed?!?!?

[jmslms]

I have had the same problem with both of my Jettas (86 and 88). They both have sat for over a year at one time before I bought them.

The engine has a high idle speed and I can't figure out the problem?
Both cars have the same problem, they have an idle of about 1700 to 2100 rpms and up to 3000 rpms if I have the a/c or defrost on. I tried everything on my 86, but never found the problem.

I just got my 88 carat and it is doing the same thing, but I wanted to see if anyone else has had the same problem and if they figured out how to fix it?? any help is greatly appriciated!!!

Thanks

[boschmann]

Try checking the auxiliary air valve. It looks like a 1" diameter cylinder with a 1" hose from the intake boot coming in one end and a 1" hose coming out the bottom going to the intake plenum. Also, it has a two pin electrical connector in the other end. It's located in front of the intake plenum. When cold if you clamp the inlet hose off it should kill the engine. If not there is an air leak somewhere. When hot you should be able to clamp off the hose with little change in the idle. If idle drops significantly the valve is stuck open. Sometimes you can clean the valve w/carb cleaner to free it up.