if you go into the diagnostic menu and select "switch test", check to see that the gas pedal is at zero when it's released and goes to max when pressed down. (should be like 128 or something) make sure the pedal is returning properly. if it is, do a calibration on the wheel/pedal.
pretty sure the computer has to se the value go to ZERO, if it's stopping at 10 or something it wont register you've "released" it.