VEHICLE WAS BEING BACKED OUT OF THE GARAGE TO REPLACE THE TRASH CAN. AFTER BACKING PART WAY OUT OF THE GARAGE WHEN I PUT THE CAR IN GEAR IT SHOT FORWARD AND I WAS UNABLE TO STOP THE VEHICLE UNTIL IT HIT THE BACK GARAGE WALL. WHEN THE VEHICLE WAS THEN PUT INTO REVERSE IT SHOT BACKWARDS, ALSO. I WAS UNABLE TO STOP THE VEHICLE UNTIL IT WAS TOTALLY OUT OF THE GARAGE. THE VEHICLE SEEMED TO ACCELERATE ON ITS OWN. DAMAGE WAS DONE TO THE FRONT END OF THE VEHICLE, THE GARAGE WALL AND THE INSIDE UTILITY ROOM AND HALLWAY.