ON THE NIGHT OF SATURDAY (AT 9 P.M.), DECEMBER 10, 2005, I DROVE MY GMC ENVOY SLT TO MICHAEL'S. WHEN DRIVING THROUGH THE PARKING LOT, MY DAUGHTER AND I HEARD A LOUD GRINDING NOISE FROM THE UNDERSIDE OF THE VEHICLE. WE PARKED THE CAR, TURNED OFF THE ENGINE, THEN TURNED THE VEHICLE ON AGAIN. SEVERAL ICONS THAT HAD NEVER BEEN DISPLAYED ON THE DASHBOARD SCREEN APPEARED, AND MY VEHICLE'S CLOCK REFLECTED 12:00. THE CLOCK WAS SET FOR THE CORRECT TIME INITIALLY, AND NEVER TAMPERED . WE SHOPPED FOR 20 MINUTES AND RETURNED TO THE VEHICLE, STARTED IT UP AND AGAIN SEVERAL ICONS APPEARED. THE CLOCK SAID 12:00 THOUGH IT WAS 9:30 P.M. WE DROVE THROUGH OUR NEIGHBORHOOD VIEWING SOME CHRISTMAS LIGHTS FOR ABOUT 10 MINUTES. AS I PULLED ONTO OUR DRIVEWAY AND BEGAN BREAKING TO STOP THE VEHICLE AND AND PARK IT OUTSIDE OF OUR GARAGE, IT DID NOT RESPOND TO BREAKING. WHEN I PUSHED THE BRAKE PEDAL DOWN HARDER, THE VEHICLE CONTINUED AT THE SAME SPEED. I SCREAMED THAT WE WERE GOING TO HIT THE GARAGE DOOR, AND AT THAT MOMENT FELT THE VEHICLE ACCELERATE ALTHOUGH I HAD THE BRAKE PEDAL PUSHED DOWN ALL THE WAY. IT SLAMMED THROUGH THE GARAGE DOOR, I QUICKLY SHIFTED INTO PARK AND SHUT OFF THE ENGINE. MY FRONT AND MY DAUGHTER'S FRONT PASSENGER DOOR COULD NOT BE OPENED AND WE SMELLED GAS. MY HUSBAND CALLED 911 AND EMERGENCY VEHICLES RESPONDED. THEY DETERMINED IT SHOULD BE SAFE BUT ASKED THE FURNACE BE TURNED DOWN SO THAT IT WOULD NOT CAUSE ANY COMBUSTION AND TO KEEP THE AREA VENTILATED..