TWO SEPARATE INSTANCES OF COMMANDED ACCELERATION WITH 2008 MERCEDES C300. PURCHASED THE CAR FROM A PRIVATE USED CAR DEALER IN SEPTEMBER 2009 WITH 10,500 MILES. ON NOVEMBER 1, 2009 I EXPERIENCED FIRST INSTANCE OF UNCOMMANDED ACCELERATION WHILE SLOWING TO A STOP IN A DRIVEWAY. ENGINE SUDDENLY ACCELERATED TO A HIGH RATE AND STRUCK A PARKED TRUCK IMMEDIATELY IN FRONT OF CAR. SHIFTED INTO REVERSE AND CAR SPED AT MAXIMUM RPM ACROSS LAWNS AND STREET UNTIL FINALLY RETURNING TO NORMAL. AT NO TIME WERE THE BRAKES ABLE TO HAVE ANY EFFECT ON SLOWING MY SPEED. THIS INCIDENT WAS NOT REPORTED TO POLICE SINCE NO SERIOUS PROPERTY DAMAGE OCCURRED. HOWEVER, I IMMEDIATELY CONTACTED DEALER FROM WHOM WE PURCHASED THE CAR. THEY CLAIMED WE NEEDED TO CONTACT MERCEDES SINCE CAR WAS STILL UNDER WARRANTY. WHEN I VISITED THE LOCAL MERCEDES DEALER THE FOLLOWING DAY, THEY INITIALLY EXPRESSED INTEREST IN INSPECTING THE CAR RIGHT AWAY HOWEVER NEARLY 2 WEEKS PASSED BEFORE THEY TOLD US TO BRING THE CAR IN FOR INSPECTION. THEY KEPT THE CAR FOR 3 DAYS AND TOLD US THEY FOUND NO MECHANICAL OR ELECTRICAL FAULTS. WE WERE GREATLY DISAPPOINTED WITH THEIR FINDINGS AND SENT A CERTIFIED LETTER TO MERCEDES USA WITH FULL DETAILS OF THE INCIDENT. THEIR REACTION WAS THAT THE VEHICLE WAS OPERATING AS DESIGNED. WE CONTINUED TO OPERATE THE VEHICLE AND ON MAY 21, 2010 A SECOND INSTANCE OF SUDDEN UNCOMMANDED RAPID ACCELERATION OCCURRED. I WAS PULLING OUT OF MY DRIVEWAY AT A SLOW RATE WHILE SLOWING TO A STOP AS ANOTHER VEH