UPON STARTING OUT AT A RED LIGHT ON A MAJOR STREET, ENGINE WENT TO FULL-THROTTLE, CAUSING A COLLISION TO THE CAR IN FRONT. OPERATOR THEN TRIED TO PUT CAR IN PARK, BUT INSTEAD WENT INTO TO REVERSE, CAR STARTED RAPID BACKING UP, THEN WENT BACK TO DRIVE AND HIT THE CAR IN FRONT A SECOND TIME. ONCE THE VEHICLE WAS IN PARK, IGNITION WAS SWITCHED OFF. VEHICLE WOULD NOT COME OUT OF PARK WITH THE IGNITION KEY ON, SO WAS STUCK IN TRAFFIC. RESTARTED CAR REMAINED IN FULL THROTTLE CONDITION. AUTO MECHANIC VERIFIED FAILED THROTTLE, $700 TO REPLACE THROTTLE, MINOR BODY DAMAGE.