Hi, I am hoping you can help. My 2006 Cobalt stalls when idling if the rear defrost is on. If I dont run the rear defrost the car runs fine. I can use the front and heat. I have had the fuel filter , spark plugs replaced and my throttle body cleaned. The shop can not locate the problem, they said the car is running fine. I have 89K miles on it. First problem I have had since I bought it in 2006.