yes..i have always told my clients not to idle the car .Get in start it and drive is my moto..as is for most of the 911 peeps
In this case i do not think is rich.....that is all..it could be many things...as Tony has said too...
i just said not to worry too much about it because it is not bad at all...and if the car would be in the right hands in the shop maybe then i would do some test.Again nothing to worry about in this 911 warming up on the drive way before it hits the road...

Ivan

Any reason why he shouldnt start it with the air cleaner off and push/pull the plate to see which direction helps/hurts the idle? It would seem this could inform if its a rich or lean issue. Wouldnt tell him why (base mixture vs ccp vs other) but its a simple/easy test.