I experienced this problem in a 2002 Camry. I was driving on the 8 up the grade back to San Diego and had the cruise control set at 70 – At some point, the car surged forward quickly getting up to over 80. I was able to correct this by dropping the car out of cruise control and applying the brake, but I know there was no floor mat involved. I would say this was a software or hardware glitch.
