Hunting when cold... Sorry, another thread

[sid86]

Hi all

Sorry to open a new thread on this subject, but after reading them all, my problem still hasn't been solved.

Car: a 1979 911 with a 3.2 engine (euro-spec).
Problem: the car hunts very erratically when cold, but not when hot. The video below was taken directly after a complete cold start. I bought the car a couple of months ago and it has done so from the beginning.
Already done: I have replaced the ICV, the CHT sensor, and checked for vacuum leaks (couldn't find any). Also the spark-wires were changed, new spark-plugs, and a new fuel-filter (and ran some cleaner through the system). None made a difference.

The mixture will be set next week on a dyno, but if possible I would like to solve the problem before that as I have the idea the solution might have an influence on the mixture.

What should be my next step? Am I missing something obvious?

When I hold the air tube going into the ICV closed, the rpm stabilizes. When I let it open, it starts hunting again.

Thanks!

[sid86]

Any suggestions?