Hi everyone,
I have just bought a Golf mk2 16v and i am having an initial startup/ idle problem. I will try to explain the problem the best I can.

When i start the car in the morning, its start fine and idles ok. When i start driving and then dip the clutch or slow downor come to a stop the revs plummet to aroung 500 and the car sometimes stalls. Then when i try to restart it sometimes it takes a bit of time as it does not really want to start. The car idles pretty bad and the car shudders as if it wants to stall and the revs are low. But after just 2-3 minutes of driving everything is fine and drives/idles/revs like a dream.
This also happens if the car has been sitting around for over 5 hours, but its ok if the car has only been sitting around for a few hours. I thought it might be the cold start valve, but i have changed this and there was no improvement. I have also changed the ISV, and the temp sensors on the side of the head. but still no improvement. I have checked all vacumm hoses and everthing seems ok. Check all earth points/strap and they seem fine as well.
All the spark plugs/leads/rotor arm and dizzy cap are new(ish). I have noticed there is no dust cap or suppression cap on the dizzp cap. Will this cause a problem???
I am thinking about changing the WUR (warmup valve/regultor).
Will a naff ECU cause this problem.

I am sort of running out of ideas, all i can say is that i think its related when the car is coldish.

Any help would be much appreciated. Thanks