Running after start problems

[TargaWatcher]

After searching the threads I have to leave this question since I can't find threads with my symptoms.

83 911 SC starts cold great (right away) but it needs to idle for about a minute or two before I can use the throttle without killing the engine. After the minute or two it's fine.
Then, If I start it hot, (within ten minutes of having driven it) I have to drive a block or so before it will idle evenly. Almost like vapor lock but it starts, although not as easily as cold. If I don't keep the revs up myself it will die until I have driven a block or more.
If I let it sit for ten to twenty minutes before starting hot everything is fine.

I have changed the fuel filter and accumulator as per 101 projects

Any ideas?
Any threads with these symptoms that I have missed?

Thanks

[B.Lane]

yes, check the auxillary air valve first..Bently manual goes over how to do that. If is sticking copen that will cause symptoms you are describing. Get rid of possible air in fule lines..run the engine and slowly open each line off the injector pump untill all air is gone and pure fuel leks out (dont catch on fire). You WUR might be faulty as well. Check your cold start switch (its located on the front of the left timing cover..check wiring and function. Check rubber boot at top of intake for cracks.

[Paul Franssen]

Yes, just after starting (which is no problem in itself), I have to keep idling for at least 10 minutes and only then slowly build up speed till I reach cruising speed, never more than maximum 7 mph, and if I try to rev her up right from the start, I die real fast, jogging oops, sorry - wrong forum.

[TargaWatcher]

Thanks B Lane

I looked up Aux Air Valve in the Bentley manual. I couldn't find how to check it. I don't think how to check it is in there.
Do you know what it does? I know what the manual says, I just don't know why it does it.
If the spring is not moving correctly or is corroded that does sound like a good candidate for my problem.

Thanks for the reply