WITH FOOT ON BRAKE PUT VEHICLE IN DRIVE, REMOVED FOOT FROM BRAKE, VEHICLE SHOT BACKWARD, THROTTLE WIDE OPEN. HIT VEHICLELE BEHIND , VEHICLE THEN SHOT FORWARD WITH THROTTLE STILL OPEN . APPLIED THE BRAKES, BUT THEY WOULD NOT HOLD BECAUSE THROTTLE WAS STILL OPEN. PUT VEHICLE IN PARK WHICH SLOWED VEHICLE DOWN. PULLED ON EMERGENCY BRAKE WHICH ALSO SLOWED VEHICLE DOWN AND MANAGED TO STOP. DEALER SAID THEY CAN'T FIND ANYTHING WRONG WITH VEHICLE. *AK