Yabo

Finally paid for a membership.. but anyway, more importantly, just inthe last 2 days, my idles started to act funny. Sometimes it will idle correctly (800 rpm or something) but it seems sometimes it idles at 1600 or so, and then the next time i drive it itll be fine again.. has anyone had this problem? Searched the archives, didnt find anything conclusive or specifically about this.

Thanks

slevy951

Welcome new member!

Sounds like either the ISV is going bad or you have a vacuum leak......

David Floyd

I think Scott is correct and welcome new member

Yabo

ISV?

David Floyd

Idle stabilizer Valve

Mark-87-951

Where is the ISV located? Can someone post a pic? I have the same problem.

Thanks in advance,

Mark

Yabo

yeah for me too (bump)

Der Cupmeister

The Idle Stabilezer Valve is hiding under the intake manifold kinda between intake runners #2 and #3. Some members with small hands have been able to change it without removing the mamifold but my fat hands couldn't get to it. Although on my '84 it is an Auxiliary Air valve . Less technically advanced (ie. cheaper) than an ISV. Any of the dismnatlers on rennlist could supply you with a nice used one. Could also be a vacuum leak.

Yabo

Hopefully someone will see this otherwise ill make a new post.. but I just did some more close observation of my problem. and it always idles fine at start up. its just after i drive for about a minute or two that the idle starts creeping up and eventually gets to the point where it maxes out at about 1600. does this make the ISV less likely, and more likely vaccum leak? or other way around?

thanks

slevy951

Try taking some carb cleaner and spray around the intake ports and vacuum lines. If idle changes where you sprayed, you have a leak in that area. The ISV is gold cylinder thing under the intake. It has a tendency to stick when they get old.

MHT

try to tap on the valve when the idle is high, if it then comes down you know the valve is the culprit.

Chris_924s

My .02 is on the Vacuum lines. I'd suspect the brake booster side.