NHTSA Complaint #10633721 — 2013 GMC SIERRA

INITIALLY I FELT THE PROBLEM AS A SLIGHT "MISSING" IN THE ENGINE UNDER VERY LIGHT ACCELERATION BETWEEN 40 MPH AND 55MPH AND MORE PRONOUNCED UNDER CONSTANT THROTTLE GOING UP GRADES ON THE HIGHWAY AT A SPEED OF ~55 MPH (1400-1500 RPM). THE VEHICLE SEEMED TO BE "LUGGING", AND THEN THE RPM WOULD INCREASE BY ~20% IMMEDIATELY FOR A SHORT DISTANCE AND THEN DROP BACK (ALL AT CONSTANT THROTTLE) TO 1400-1500 RPM. WHEN DRIVING ON THE HIGHWAY IN CRUISE CONTROL AT 60 MPH AND GOING UP A GRADE, THE VEHICLE WOULD SHOW SIGNS OF "STRAINING" AND IMMEDIATELY INCREASE IN THE RPM BY ABOUT 20% WITH AN ATTENDANT ACCELERATION. THEN THE RPM WOULD INCREASE INSTANTLY BY ABOUT 1000 RPM AND THE VEHICLE ACCELERATES RAPIDLY UNTIL I ENGAGE THE BRAKES. MY DEALER OBSERVED THE SAME CHARACTERISTICS AND DETERMINED THAT IT WAS A TORQUE CONVERTER PROBLEM AND ON 07/25/2014 THEY INSTALLED A NEW TORQUE CONVERTER, WHICH PROVED TO HAVE NO EFFECT ON THE PROBLEM. I WAS INFORMED BY THE SERVICE MANAGER THAT GMC TECHNICAL SERVICES INFORMED HIM OF A SERVICE BULLETIN (#PIP4681D: RANDOM BUMP CHUGGLE OR FISHBITE SENSATION WHILE CRUISING AT APPROXIMATELY 1,300 RPM- OCTOBER 31, 2013) THAT ADDRESSED THE PROBLEM, AND FURTHERMORE NO FURTHER CORRECTIVE ACTION COULD BE TAKEN. ON AUGUST 6,,2014 I WAS DRIVING AT CONSTANT SPEED OF 60 MPH ON A MAJOR HIGHWAY IN "CRUISE CONTROL" AND MODERATE TRAFFIC. WHILE GOING UP A LONG GRADE FOLLOWING ANOTHER VEHICLE AT A SAFE SPEED, MY VEHICLE IMMEDIATELY JUMPED ~400 RPM AND THEN ABRUPTLY CHANGED TO A LOWER GEAR AND ACCELERATED SUDDENLY PUTTING ME AT RISK OF COLLIDING WITH THE VEHICLE AHEAD OF ME. I QUICKLY APPLIED BRAKES AND WAS ABLE TO AVOID AN ACCIDENT. I IMMEDIATELY CONTACTED GMC CUSTOMER SERVICES WHO OPENED A CASE NUMBER ([XXX]) AND ASSIGNED A REP. TO MY CASE. I HAVE SUBSEQUENTLY BEEN INFORMED OF THE GMC COMPANY LINE--"THE VEHICLE IS OPERATING AS DESIGNED", "LIVE WITH IT"!!! INFORMATION REDACTED PURSUANT TO THE FREEDOM OF INFORMATION ACT (FOIA), 5 U.S.C. 552(B)(6). *TR