Sudden acceleration, caused by driver's loose floor mat. started car in garage. in park, engine ran at 4,000 rpm from start. tried to kick down gas pedal several times, no change. ignition on and off three times, no change. pressed firmly on the brake, shifted to reverse. i knew it would lurch. got out of garage, pressing firmly. rpms dropped to normal 1,000 range. shifted into drive, car rpm increased to 4,000 rpm and lurched. sat there for five minutes thinking it would settle down. nothing. i then decided to check the floor mat. it was on top of the gas pedal. it had moved forward because the one of the securing locks on the mat had broken free