PUT CAR IN REVERSE TO BACK UP. CAR ACCELERATED AT HIGH SPEED (40-60 MPH) WITHOUT PUTTING FOOT ON ACCELERATOR. UNABLE TO STOP CAR DESPITE BRAKING AND PUTTING CAR INTO PARK. HIT TREES MAILBOX AND HOUSE BEFORE COMING TO A STOP IN A DITCH. CAR INVESTIGATED BY DAIMLER-CHRYSLER NO DEFECT FOUND. DT