88 80: Lumpy idle when hot

[Tom Nas <tnas@euronet.nl>]

Hi all,

I've posted this a week ago, but have received no replies. Is there really
no-one who could hazard a guess, or maybe had this problem too? So, here
goes again:

Here's one I can't figure out myself: my (carb'd/cat) 1988 80 1.8S idles
beautifully when cold, almost inaudible and silky-smooth at 400-500rpm.
When things get hotter however, idle goes to 1100-1200rpm and becomes
rather lumpy, to the point where the whole car is shaking sometimes.

It's been tuned a few times, all hoses have been checked/replaced. Being a
non-injected car, does this have an ISV? Can't find anything in the Book...

Ideas, anyone?

TIA!

Tom

 _______________________________________________________________________
 Tom Nas                                          Zeist, The Netherlands
 tnas@euronet.nl
1988 Audi 80 1.8S, Tizianrot metallic, 212,000km

  Half a bee, philosophically, must ipso facto half not be. But can it be
  an entire bee, if half the bee is not a bee, due to some ancient injury?

                                                -- Monty Python