I PULLED INTO THE DRIVEWAY BEHIND 2 PARKED CARS. I STOPPED AND PUT MY TRUCK IN PARK AND WHEN I TOOK MY FOOT OFF THE BRAKE THE TRUCK REVVED UP AND WENT FORWARD, I STEPPED ON THE BRAKE TO STOP THE TRUCK, BUT THE BRAKES FAILED TO STOP THE TRUCK FROM RUNNING INTO THE 2 CARS. AS I KEPT PRESSING THE BRAKE THE TRUCK'S ENGINE WAS REVVING AND THE TIRES WERE BURNING RUBBER, I KEPT PRESSING THE BRAKE AND THE TRUCK WOULD NOT STOP IT WAS OUT OF CONTROL. THE TRUCK RAMMED INTO BOTH CARS PUSHING ONE OF THEM INTO THE SIDE OF THE NEIGHBOR'S YARD. ALL THIS HAPPENED WHILE THE TRUCK WAS IN PARK. I PULLED BACK TO REVERSE SO I COULD GET OFF THE CAR AND WHEN I TOOK MY FOOT OFF THE BRAKE THE TRUCK CONTINUED REVVING THIS TIME GOING IN REVERSE, AGAIN I KEPT PRESSING THE BRAKE, BUT THE TRUCK WOULD NOT STOP IT WAS OUT OF CONTROL. IT WENT IN A HALF CIRCLE GOING INTO THE NEIGHBOR'S FRONT YARD KNOCKING DOWN A 6 INCH WALL, SOME BUSHES AND RUNNING INTO A TREE. THE TRUCK STOPPED AND TURNED OFF BY ITSELF AFTER HITTING THE WALL, THE BUSHES AND THE TREE. THIS INCIDENT CAUSED A LOT OF DAMAGE AND TOTALING ONE OF THE CARS. I DON'T KNOW WHAT CAUSED THE TRUCK TO GO FORWARD WHILE IN PARK, THE BRAKES NOT TO WORK AND THE ENGINE REVVING UP. I BELIEVE THE PARTS AFFECTED ARE THE BRAKES, THE POWER TRAIN AND SPEED CONTROL.