Audi 200 Ti - strange problem

[Christo Atanasov]

Hi there,
few days ago I decide to bye another car, so I can drive something until
resurect my Quattro.
I found a good Audi 200 from 1985, but it has a problem. The boy that sell
this car told me that engine runs good, till it's cold
but when warms up, it has no idle revs and dies. I think this may be faulty
Warmup regulator, or ISV valve or ISV control device,
but I'm not so sure.. is it possible to have another more expensive reason
for this problem?
This car has KG Engine, and what I know for this engine.. it is 2.1 (79.5mm
bore) like older engines, but whit knock sensing ignition..
It has WarmUp regulator, so it must be K-Jetronic instead of later
KE-Jetronic.

Regards,
Christo Atanasov