Idle stabilizer valve for 1990 Corrado G60

[Volkswagen]

Hello,
How do you know when the ISV is going bad? My symptoms are: 1) Idles
at 1000 rpm when just started in the morning. 2) After I tap on the
gas it goes to 1500 rpm and stays there the majority of the time. 3)
Every blue moon or so the idle jumps to a whopping 2000 rpm then it
will eventually go down to 1500 rpm again. All of this occurs when I
am idling. Can this be a sign of a faulty ISV? I don't know if any
of the mods done to the car should do this, but what has been done is
P-chip, cam w/adjustable sprocket, and HP kit w/o pulley.

BTW, I was just wondering if the G60 is a loud engine? Not
considering the supercharger, just the engine itself.

TIA,
Alfred
Silver Corrado G60

[Olivier Teko]

I had the same problem but last week i bought a can of "Kleen-Flo Air
admission system cleaner" I bought that at my VW dealer for 6 canadian
bucks; he said that's the only one VW approves. But anyways it took half
of the can to get the ISV in shape.
I hope this can help,

Olivier Teko

ot...@acica.com

[Gregory B. Tibbs]

Yup, it sounds like the ISV is bad. To know for sure, get the car
to idle high, stop and open the hood, and then tap the ISV with the
plastic end of a large screw driver. If the idle drops to normal, then
the ISV is sticking and needs to be replaced.

Some have claimed that the ISV can be cleaned, mine didn't respond to
cleaning and replacement was the only choice.

BTW, it's expensive.

-Greg