I have posted before on this problem but need to give everyone a heads up and what to be aware of. I purchased my 2011 Mustang new in June of 2010. Immediately I noticed that once in a while the air conditioner would blow warm air. It would last only a few seconds and then go back to cold where it usually stayed. This summer the air started blowing warm as often as cold. The hotter the ambient temperature the hotter and longer it would blow. At 90 degrees outside temp it had a swing in air conditioning temp of 15 degrees. At 100 degrees the temp differential was more than 15 degrees and would blow hot air more than cold. I have had the car in 5 times now. Ford engineers got involved and they just notified me that they consider this temp differential to be within normal limits. Thats BS as I have purchased 5 new fords over the years and none of them had this trait. The dealership drove three new mustangs they had on the lot and couldn't get any of them to do this. My Fusion 4 banger loaner car does not have any temp differential. Ford has tested and re tested all the components and cannot figure out how to fix it. Ford has told me to pick up my car and they will not address the issue anymore. I was hoping it would not come to this as I have a few hundred in aftermarket improvements in the car but I am in contact with a lemon law lawyer as I feel it is my last option. What a shame! Hope no one else has to go through this but if you notice a temp differential in you air conditioning expect it to get worse with no fix from Ford.