I TURNED RIGHT INTO THE PARKING LOT AND PROCEEDED APPROXIMATELY 120 FEET AND TURNED RIGHT INTO THE FIRST AVAILABLE PARKING SPOT. THERE ARE SPEED BUMPS IN PARKING LOT THAT DO NOT ALLOW ANY SPEED TO BE GAINED BETWEEN DRIVEWAY AND PARKING SPOT. AS SOON AS MY CAR ENTERED THE PARKING SPOT, AND WITH MY FOOT STILL ON THE BRAKE, THE VEHICLE SUDDENLY ACCELERATED AND SURGED FORWARD JUMPING THE PARKING CURB AND HITTING THE OUTSIDE OF THE DENTAL BUILDING. THE VEHICLE LUNGED FORWARD OVER THE PARKING CURB, THROUGH SHRUBBERY, STRUCK A PARKING SIGN AND FINALLY THE BUILDING, A TOTAL DISTANCE OF ABOUT 6 FEET, BEFORE STOPPING. THE SITUATION HAPPENED ONLY ONCE AND WAS ENOUGH FOR US TO REQUEST LEXUS TO BUY THE VEHICLE BACK FROM US. LEXUS LOOKED AT THE FLOOR MATS AND DEEMED THEY WERE SECURELY IN PLACE NOT CAUSING THE ACCIDENT. THEY CHECKED THE CAR MECHANICALLY AND COULD FIND NOTHING WRONG & NO COMPUTER ERROR CODES RECORDED. THEY DID ABSOLUTELY NOTHING TO THE VEHICLE AND RETURNED IT TO US CLAIMING NO MALFUNCTION OF THE CAR. THE FRONT BUMPER AND HOOD NEEDED REPLACEMENT AND WE HAD TO PLACE AN INSURANCE CLAIM AND PAY OUR DEDUCTIBLE TO GET THE CAR REPAIRED. *TR