83 911 SC idle problem
 

Cold idle 600rpm Warm idle 1300 rpm

Cold is what temperature?
60, 70 80, 90F?

If it's low enough, there is a supplementary air feed that has a disc sliding by an opening allowing more or less air to pass through, dependent on temperature. The air feed becomes restricted gradually once car is started through a heating element and engine temperature. auxiliary air regulator, aar.

Did you dial up the air bypass screw recently to compensate for cold running?
Did the idle rpm suddenly just increase to 1300 while warm?
What was it before?



Phil

I have an 83SC as well. Does yours still have a working lambda (O2) system? Have you done anything to the car recently? Do you know how to look for vacume leaks or check to see if the mixture is about right? Does it run smoothly and start ok when hot? How many miles on the motor?
If you remove the oil tank cap does the idle drop a bit?

A few more details would help.