VEHICLE RAPIDLY ACCELERATED ON ITS OWN AFTER I SLOWED DOWN THE VEHICLE TO PARK IN MY GARAGE. I HEARD AN ENGINE REVVING NOISE PRIOR TO THE VEHICLE SUDDENLY ACCELERATING. IT WENT THROUGH THE BACK OF MY GARAGE, OVER THE DECK AND FIINALLY WAS STOPPED UPON IMPACT WITH A TREE STUMP IN THE BACKYARD. SIDE AIR BAGS DEPLOYED BUT FRONT DID NOT.