You need to find the vacuum leak. It is going to be anywhere from the mode switch on to the hoses and actuators. Start with the mode switch if it hisses. David Teitelbaum vin 10757 --- In dmcnews@xxxxxxxxxxxxxxx, id <ionicdesign@xxxx> wrote: > When the engine warms up to running temp the cold idle hunting is gone. > > I turn on the A/C with a warm engine and the idle hunts again. > > I turn off the A/C with a warm engine the hunting is gone. > > What is wrong? > > Mark > 6683