ABOUT 4 WEEKS AGO (3000 MILES) MY SPEEDOMETER BEGAN TO PERIODICALLY MALFUNCTION. IT WOULD BEGIN TO SHOW ACCELERATION IN EXCESS OF 120 MPH EVEN THOUGH I WOULD BE TRAVELING AT SPEEDS LESS THAN 45 MPH. ONCE THE VEHICLE WAS TURNED OFF IT WOULD SEEM TO WORK NORMALLY. THIS PROBLEM QUICKLY DEVELOPED INTO A FULL-TIME PROBLEM. NOW WHEN MY VEHICLE IS IN PART IT MAY REGISTER FROM 70 TO 90 MPH. I TOOK THE VEHICLE TO THE GMC DEALER FOR A QUOTE AND WAS TOLD THAT THEY HAD FIXED THIS SAME PROBLEM ON A NUMBER OF YUKONS AND THAT I NEEDED A NEW INSTRUMENT CLUSTER. *JB
2011
ENGINE
THE VEHICLE SUDDENLY LOST POWER AND THE STABILI-TRAC SYSTEM WARNING APPEARED IN THE DIC, THEN THE TRACTION CONTROL SYSTEM WARNING APPEARED IN THE DIC, THEN ENGINE POWER REDUCED BY 16% IN THE DIC. DROVE VEHICLE TO EXIT RAMP AND TURNED ENGINE OFF. VEHICLE RESTARTED WITH ONLY THE CHECK ENGINE LIGHT ON AND NO WARNINGS IN THE DIC. THE ENGINE DID NOT HOWEVER RUN SMOOTHLY. I TOOK IT TO A DEALER WHO CLEAR SOME CODES AND REPLACED THE TPS. CHECKED ALL FUSES. NO FURTHER PROBLEM. HOWEVER A FRIEND HAS THE SAME VEHICLE IN A 2010 MODEL. SAME PROBLEM DEALER REPLACED A THROTTLE BODY. CHECK OUT THE GM FORUM AT HTTP://TOWNHALL-TALK.EDMUNDS.COM/DIRECT/VIEW/.F0E807E/0 THIS FORUM SHOWS LITERALLY HUNDREDS OF COMPLAINTS ABOUT THE SAME PROBLEM AND IN SOME CASES CAUSING ACCIDENTS. MY VEHICLE WAS REPAIRED ON 1-24-2013, AND SO FAR IT APPEARS THAT MY PROBLEM HAS BEEN RESOLVED, HOWEVER IT APPEARS GM IS NOT REALLY FIXING THE PROBLEM. I AM CONCERNED ABOUT THIS FOR THE NEXT OUT OF TOWN TRIP I TAKE. *TR
