There are 7 owner-reported engine complaints for the 2014 GMC Sierrain NHTSA's database. These are unverified consumer reports and may not reflect confirmed defects.
#5 CYLINDER ROCKER ARM BROKE TOOK TO A DEALERSHIP IN MICHIGAN TO GET REPAIRED. PROBLEMS WITH ENGINE RUNNING, BEFORE ALL THIS HAPPENED I WAS GETTING 20/22 MPG ON THE HIGHWAY WHICH IS WHAT I TRAVEL MOSTLY, NOW SINCE THIS HAPPEN I ONLY GETTING 16/18 MPG ON THE HIGHWAY. MY DEALERSHIP IN MILWAUKEE WORKED WITH AN ENGINEER FROM GM AND THEY CLAIM EVERYTHING UP TO SPEC AND WON'T DO ANYMORE ON THE VEHICLE BUT YET SOMETHING HAS HAPPENED THAT I HAVE LOST ABOUT 4/6 MPG HIGHWAY OR $20 PER TANK WHICH WITH MY TRAVELING IS A LOT OF MONEY $400 MONTH. I AM VERY DISSATISFIED WITH GM AND THIS VEHICLE RIGHT NOW WHEN YOU PAY $50,000 + FOR A VEHICLE YOU DON'T EXPECT TO HAVE PROBLEMS WITHIN THE FIRST MONTH OF PURCHASE (BRAND NEW) AND THEN FOR GM NOT TO FIND OUT WHY THE DROP IN MILEAGE IS UNACCEPTABLE. *TR
MY SON AND I WERE DRIVING MY GMC SIERRA 2014 TO HIS FRIENDS HOUSE BEFORE WE CRASHED. MY SON WAS DRIVING AND HAS HIS LEARNER'S PERMIT, HOWEVER, HAD BEEN DRIVING FOR 4 MONTHS. AT A FORK IN THE ROAD I TOLD MY SON QUICKLY TO MAKE A RIGHT RATHER THAN LEFT AND WE CRASHED INTO AN IMPROPERLY GRATED WALL OF DIRT CAUSING THE TRUCK TO GO FROM 40 MPH TO 0 WITH MY SON HAVING HIS SEATBELT ON, BUT I DID NOT. NEITHER AIRBAGS DEPLOYED AND BOTH OF US SUSTAINED SERIOUS INJURIES. MY SON BROKE HIS NOSE AND I AM SUFFERING FROM A BROKEN NOSE, CONCUSSION AND A BURST VERTEBRAE. NEITHER AIRBAGS DEPLOYED WHICH COULD'VE MADE A HUGE DIFFERENCE ON OUR INJURIES. *TR
VEHICLE WAS PURCHASED NEW FROM A DEALERSHIP. THE VEHICLE IS MODIFIED AND SOLD COMMERCIALLY UNDER THE RMT (ROCKY MOUNTAIN TRUCK WORKS) PACKAGE. THE PACKAGE INCLUDES MODIFIED SUSPENSION AND LIGHTING. WHEN ACCELERATING, THE TRANSMISSION FAILS TO SHIFT INTO A PASSING GEAR CAUSING THE RPM(S) TO EXCEED 6000 AT WHICH POINT THE REV LIMITER SHUTS DOWN POWER TO THE VEHICLE UNTIL THE RPM(S) ARE BACK IN A SAFE OPERATING LIMIT. THE FIRST TIME THIS HAPPENED, I WAS ATTEMPTING TO PASS A VEHICLE ON A SECONDARY TWO LANE HIGHWAY. WHEN I WAS IN THE PASSING LANE, I ACCELERATED TO OVERTAKE THE VEHICLE BUT THE RPM LIMITER SHUT DOWN POWER MIDWAY THROUGH THE PASSING. WITH ONCOMING TRAFFIC, AND LOSS OF POWER, IT MADE FOR A VERY SERIOUS SITUATION. I HAVE CONTACTED THE DEALERSHIP AND THEY HAVE WORKED ON THE VEHICLE MULTIPLE TIMES TO TRY AND CORRECT WITHOUT SUCCESS. THEY HAVE CONFIRMED THAT THIS HAPPENING WITH ALL THE RMT MODIFIED VEHICLES THAT THEY HAVE TEST DRIVEN. THESE VEHICLES ARE COMMERCIALLY MARKETED AND IT IS ONLY A MATTER OF TIME BEFORE SOMEONE IS NOT AS LUCKY AS I WAS. *TR
BRAKE AND THEN ACCELERATE LOSSES POWER TRANSMISSION SLIPS. WHEN TRYING TO MERGE TO FREEWAY I BRAKE AND THEN TRY TO ACCELERATE IT LOOSES POWER TRANSMISSION SLIPS. *TR
THE VEHICLE HAD BEEN PARKED FOR OVER THREE HOURS AT WHICH TIME IT WAS ENGULFED IN FLAMES. THE ENTIRE ENGINE COMPARTMENT CONSUMED BY FIRE. WE HAD TAKEN THE VEHICLE 2 WEEKS EARLIER TO A DEALER TO HAVE THE RECALL COMPONENT REPLACED BUT IT APPEARS THAT THE PROBLEM WAS NOT CORRECTED AND NOW WE HAVE A VEHICLE WHICH WAS ONLY 4 MONTHS OLD AS A PIECE OF WORTHLESS PILE OF METAL. GM HAS BEEN SLOW TO REACT TO THIS ISSUE AND HAS REQUESTED THAT WE FIRST HAVE OUR INSURANCE COMPANY LOOK AT THE VEHICLE VS. SEEM SEND THEM ONE TO LOOK AT THE THIS. *TR
I HAD MY TRUCK'S ECM REPROGRAMMED LAST FRIDAY (1/17) DUE TO RECALL #14V007, AND EARLIER THIS EVENING (1/24) THE CHECK ENGINE LIGHT CAME IN AND THE DIC SHOWED AN "ENGINE POWER IS REDUCED" MESSAGE. THE ENGINE RAN VERY SLUGGISH AND I PARKED IT AS GM RECOMMENDED TO DO IN THEIR RECALL LETTER. THIS IS THE SECOND TIME THIS HAS HAPPENED NOW. I THOUGHT THAT THE NEW SOFTWARE WAS SUPPOSED TO CORRECT THAT ISSUE? *TR
VEHICLE HESITATES AND STALLS UPON ACCELERATION. ACCORDING TO GM DOCUMENT ID NUMBER [XXX] THIS IS A NORMAL CONDITION AND THEY HAVE PROGRAMMED THE VEHICLE TO DO THIS. IF GOING INTO TRAFFIC AND TRYING TO ACCELERATE, THE BUILT IN DELAY CAN CAUSE CLOSE CALLS AT BEST AND WORST CASE AN ACCIDENT. THIS COUPLED WITH THE TRANSMISSION ISSUES MENTIONED IN DOCUMENT ID NUMBER 3575856 CREATES THE PERFECT STORM FOR INJURY AND / OR DEATH. GM REFUSES TO ADDRESS THE ISSUE OTHER THAN TO SAY THEY FEEL IT IS NOT A PROBLEM. THIS COVERS VIRTUALLY ALL GM VEHICLES SINCE 2007 WITH THE 6 SPEED TRANSMISSION. INFORMATION REDACTED PURSUANT TO THE FREEDOM OF INFORMATION ACT (FOIA), 5 U.S.C. 552(B)(6). *TR
Complaints are unverified consumer reports submitted to NHTSA. A high complaint count may reflect vehicle popularity, not defect severity. Data sourced from NHTSA public records.
Data synced from NHTSA on Apr 25, 2026