This is the forth time my rotors having warped in the past 7k miles. The first time I had the rotors turned and I installed new brake pads. The second time Ford replaced the pads and turned the rotors. Third time ford replaced the rotors. Now there warped again. Keep in mind I have a Bullitt with twin piston calipers and 13" rotors. Any ideas what might be causing the problem. I drive the car like its a mustang but I don't hammer the brakes down all that often. Most of my driving is interstate. Thanks for any suggestions.