ON 4 SEPARATE OCCASIONS WITHIN A 3 WEEK PERIOD THE VEHICLE WOULD ACCELERATE WHILE DRIVING WITHOUT DRIVER PROMPTS OR CONTROL (RPMS REVVED FROM 2000 TO OVER 6000 AND SPEED WOULD INCREASE FROM 50 MPH TO OVER 85 MPH WITH ACCELERATOR PEGGED TO THE FLOOR.) THE ONLY WAY TO CORRECT THIS WAS TO PUT THE VEHICLE IN NEUTRAL, COAST TO THE SIDE OF THE ROAD, STOP THE VEHICLE AND TURN OFF THE ENGINE FOR 10-15 MINUTES, THEN RESTART IT AND IT WOULD RUN NORMALLY FOR SHORT PERIODS OF TIME. IF I DROVE THE VEHICLE FOR MORE THAN 30 MINUTES AT A TIME IT WOULD REACT THIS WAY EVERY TIME AND NEARLY CAUSED ME TO HIT 2 VEHICLES ON THE INTERSTATE. ON ONE OCCASION I HAD TO IMPACT A GUARDRAIL TO SLOW THE VEHICLE DOWN. I TOOK THE VEHICLE TO A CERTIFIED GMC DEALERSHIP WHO STATED ON BOTH OCCASIONS THEY COULD NOT REPEAT THE PROBLEM AFTER DRIVING IT FOR 5-10 MINUTES OR LESS THAN 15 MILES. WHEN I INFORMED THEM THAT IT ONLY OCCURRED AFTER 30-45 MINUTES OF DRIVING, THE TECHNICIAN STATED HE DIDN'T HAVE TIME TO DRIVE THE VEHICLE THAT LENGTH OF TIME OR DISTANCE AND WENT ON TO SAY NO DIAGNOSTIC CODES WERE TRIPPED SO THERE WASN'T ANY REPAIRS HE COULD DO OR THAT GMC WOULD AUTHORIZED. THE VEHICLE WAS UNDER WARRANTY. I RESEARCHED THIS PROBLEM ONLINE AT WWW.CARCOMPLAINTS.COM AND FOUND OVER 25 SIMILAR ISSUES AND COMPLAINTS FROM OTHER OWNERS OF THE SAME YEAR MAKE AND MODEL. TWO OF WHICH RESULTED IN A CRASH WITH SERIOUS INJURIES TO THE OCCUPANTS. I WAS FORCED TO SELL THIS VEHICLE AT A 2554.00 LOSS AND WILL NOW BE FILING A CLA