A number of 2011 Mustang GT owners have recently reported experiencing a problem with the clutch pedal returning after a hard or high rev shift. Apparently the pedal may not return easily after being pushed to the end of its travel. A significant change in the design of the 2011 pedal mechanism can be seen in these photos. The one shows the 2011 GT design and its operation is illustrated in the video below. The complaint is apparently not universal, suggesting that some variation may be leading the clutch return spring to act more like an over-center spring. According to reports, the pedal must be pushed most or all the way to the floor for this to happen.
This photo shows the clutch pedal box from the 2010 GT500 Mustang. Note that the clutch pedal return spring is a rotary spring, similar to that used for the brake pedal.
Lethal Performance is reporting, via SVTPerformance.com, that the solution is to replace the current clutch pedal box with one from a 2010 GT500 Mustang. They report that smooth, consistent action and trouble-free returns are restored using the new pedal box.