A strange problem
 

My car has this new problem where on occasion, the idles will just dive. Sometimes causing the car to stall. It doesnt do it at any particular point or RPM, just when it feels like it! Its difficult to describe. It is almost like hitting the rev limiter, but without revving out the car, and as soon as it happens it normally goes back to idle. Also, sometimes when the car is a bit cold, the idle will rev to about 1600, then drop to about 800 or 700, and keep going back and forth. Does anyone have a clue on either question? Any help would be greatly appreciated! Thank you!

sounds like it could be the idle stabilizer valve going out.

Or a vacuum leak.

What does the vacuum leak do? How would I be able to tell? Thanks.

spray some carb spray or propane around the rubber hoses and air intake areas......when the idle increases........there's your leak.....if there is one.......vas

My 86 Turbo had this problem at idle only.

It was a .25 cent "O" ring on the idle mixture screw. The one that sits in top of the throttle body. It had stretched to the point were it was sucking air in.

This might be your problem too.

[This message has been edited by Kevin C (edited 03-18-2001).]

Hey 2young944
I had the same problem appear when I cleaned my throttle body with carb cleaner. What happened is that the throttle was letting in alot more air now that all the dirt is gone, so what happened is that the idle screw (or throttle mixture screw) had to be adjusted to let in less air than it was before the cleaning. The rpm basically rises because of the increased air flow (idle screw adjustment, or faulty O ring, or leaky vacuum hose) then the DDE kicks the rpm down when it detects that it's too high ... and hence you get the oscillation in rpm.
Hope this helps,
good luck