I bought an 05 V6 Mustang in May. The car runs fine except for one small problem...the RPM's have a mind of their own. It is fine when I'm in gear, however, once I let it idle at a stoplight or stopsign the RPM's go crazy. The go up and down anywhere from 700 to 2500, just back and forth. I have taken it to 2 different dealerships and no one can find anything wrong with it. I also had a miserable experience by calling the Ford nationwide hotline. They were rude and had no ideas for possible solutions. I was hoping someone out there had some.

 

sounds like a bad computer.