2021 GMC Yukon: misfire or rough idle

Filed Oct 20, 2026 · Engine, Transmission · PA

VEHICLE: 2021 GMC Yukon, 5.3L V8 (L84). VIN: [XXX]. Mileage at failure: approximately 88,000. Component: Engine. INCIDENT DATE: XXX While I was driving on a highway, the engine began to misfire and I heard a ticking noise. The check engine light then began flashing, indicating a severe misfire. I pulled off the highway immediately to a rest area. The vehicle was towed to a GMC dealer. The dealer's diagnosis suspected failed valve lifters, and the repair orders call for a misfire diagnosis with the Bank 1 cylinder head removed, and replacement of the camshaft, lifters, and related parts. This failure caused sudden loss of engine performance at highway speed. The engine began smoking. My family and I were in the vehicle, and we were fortunate there was a safe place to stop. I believe this is a known defect. GM Service Bulletin PIP5776, "Misfire Due to Collapsed Lifter," covers 2021 GMC Yukons with the 5.3L L84 engine. It describes a misfire with a bent pushrod leading to a collapsed lifter or a lifter that comes apart, and it attributes the cause to an internal lifter concern. Many other owners of GM V8 trucks and SUVs have reported the same failure, and a class action over the AFM/DFM lifters has been pending against GM in federal court in [XXX] since 2021. I bought this vehicle new and have maintained it. This is the second time this vehicle has left my family stranded on a highway. In 2024, a separate known issue left us, including three children under [XXX], on the side of a major highway about 7 hours from home. GM repaired that issue. For the current failure, GM has not agreed to cover the repair. It has offered $5,951.39 toward an engine replacement, which would leave me responsible for $13,886.59 plus teardown labor. I am filing this complaint so the federal safety agency is aware of this failure, which can cause sudden loss of power on the highway. GM case number: XXX. Dealer: Fred Beans Buick GMC, [XXX]. INFORMATION REDACTED PURSUANT TO THE FREEDOM OF INFORMATION ACT (FOIA), 5 U.S.C. 552(B)(6)

Filed Sep 3, 2026 · Engine · MS

My 2021 GMC Yukon began experiencing severe engine problems, including shaking/rough running, a noticeable ticking/knocking noise from the engine, and a flashing check-engine light. The vehicle also displayed Service ESC and traction control warnings and exhibited symptoms of an engine misfire. I took the vehicle to a dealership for evaluation. I was advised that the problem may involve failed lifters and that the vehicle could be out of service for several weeks for repairs. I was also advised that the repair could be very costly. At this time, I have not been given a final diagnosis, so the exact internal engine component responsible for the failure is UNKNOWN. I am concerned that the condition presents a safety risk because the engine is running extremely rough and the check-engine light is flashing. I am afraid the engine could lose power or fail while the vehicle is being driven, potentially putting me, my passengers, and other motorists at risk. I have also become aware of the federal safety agency's investigation involving failures of the 6.2-liter L87 V8 engine in GM vehicles, including the GMC Yukon, as well as reports of engine failures occurring after certain repairs or recall remedies. This has increased my concern about whether repairing or replacing individual engine components will permanently resolve the problem. I am submitting this complaint so that my vehicle's symptoms, dealer evaluation, and potential engine failure are documented. The vehicle and affected components are available for inspection upon request. The dealership has evaluated the vehicle, but a final determination of the exact cause has not yet been provided.

Filed Sep 1, 2026 · Engine · TX

My 2021 GMC Yukon Denali with approximately 88,000 miles developed a significant engine knocking noise and was towed to a GMC dealership for diagnosis. The dealership confirmed diagnostic trouble code P0301 (engine misfire) and documented a “knocking noise in lower end at piston rod crankshaft area.” The dealership advised that my vehicle is not currently included in the existing GM recall for certain 6.2L L87 engines. The vehicle has the 6.2L L87 V8 engine. I am concerned because the documented knocking is located in the lower engine area involving the piston/connecting rod/crankshaft area, which is consistent with the type of internal engine failure associated with the L87 engine investigation and recall. I am concerned about the possibility of sudden engine failure and loss of propulsion while driving. I am requesting that the federal safety agency investigate this failure and consider whether vehicles outside the current recall population should also be included. I also recently experienced an engine replacement on another 2024 GMC vehicle. I am providing that information as additional customer experience, but I am not claiming that the two failures are necessarily caused by the same defect.

Filed Jul 27, 2026 · Driver assistance, Engine · 86,000 miles · MA

The contact owns a 2021 GMC Yukon. The contact stated that while driving at an undisclosed speed, there was a misfire coming from the vehicle, the vehicle was shaking and vibrating abnormally before the vehicle went into LIMP Mode. The traction control light and other unknown warning lights were illuminated on the instrument panel. The vehicle was taken to a dealer to be diagnosed. The vehicle was diagnosed with a lifter failure inside the engine. The vehicle was not repaired. The manufacturer was notified of the failure. The failure mileage was 86,000.

Filed Jun 30, 2026 · Driver assistance, Engine · FL

I bought the vehicle used with 40,000 miles it’s has 100,856 now the engine shot off while I was driving and brought it to the GMC dealer that GM instructed me to the dealer had me pay 284.95 for inspection and then try to charge me 1284.95 for a complete tar down of the engine because of misfiring and ESC error codes.

Filed Jun 11, 2026 · Engine · FL

On May 27, 2026, I was on my way home from work when I went to accelerate the vehicle and all the sudden it started shaking and the check engine light came on with the EBS. I was able to get the vehicle to a repair shop local the next day, who took the car apart. What was thought to be an easy fix of spark plugs and fuel injector, became even more after they put back together and the cylinder was still misfiring. After several hours of taking apart the engine, the mechanic determined that the hydraulic valve lifters had failed. This has been an ongoing issue with with the 5.8L V8. Due to a recall not being under the vin yet, i have now incured a $16k expense to add an engine to it after i purchased it in Nov of 25 at $97,000. This is a saftey issue and luckily no one was hurt when the car started shaking and couldn't go over a certain speed. I want this reviewed and looked at for possible reimbursement as there have been several other vehicles with the same known issue.

Filed Jun 5, 2026 · Engine · OK

I am filing a complaint regarding my 2021 GMC Yukon due to a serious engine failure involving the camshaft, lifters, and crankshaft. The vehicle began exhibiting engine ticking and knocking noises, rough idle, loss of power, and reduced performance. These symptoms progressively worsened and ultimately resulted in major engine damage. The vehicle was diagnosed with failed lifters and camshaft damage, which required extensive repairs. In addition, the crankshaft failed, resulting in catastrophic engine damage and making the vehicle unsafe to operate. These are critical engine components that should not fail prematurely under normal driving and maintenance conditions. The most serious concern is safety. The engine's loss of power and deteriorating performance created the risk of sudden failure while driving. A vehicle that loses power in traffic, while merging, crossing intersections, or traveling at highway speeds can create a dangerous situation and increase the risk of a crash. Occupants and other motorists could be placed at risk if the engine fails without warning. My vehicle has been properly maintained and serviced. Despite regular maintenance, these major engine components failed unexpectedly. I am aware that other owners of GMC and Chevrolet vehicles equipped with similar engines have reported comparable camshaft and lifter failures, suggesting a potential defect rather than an isolated incident. The failure resulted in significant repair costs, loss of vehicle use, and concerns about the long-term reliability and safety of the vehicle. I believe these engine failures may indicate a manufacturing or design defect affecting 2021 GMC Yukon vehicles. I respectfully request that the federal safety agency investigate camshaft, lifter, and crankshaft failures in the 2021 GMC Yukon and determine whether a safety-related defect exists that warrants corrective action or a recall.

Filed May 28, 2026 · Engine · AZ

Engine is misfiring. Took it into local mechanic who mentioned he has seen many similar issues and knew there was a recall for similar 2021 Yukon engine issues but for some reason this model was not included. He encouraged me to trade in the vehicle because most likely the engine would need to be replaced (or a $10,000 repair) and it was not save to continue to drive in this condition. I call GMC and they suggested I contact the federal safety agency to request that this year and model be added to the recall listing for other similar Yukon engines.

Filed May 26, 2026 · Engine · NY

The contact owns a 2021 GMC Yukon. The contact stated that the vehicle had a rough idle. There was an abnormal ticking and rattling sound detected. The vehicle lost oil pressure. The contact located smoke emerging from the vehicle. The engine light was illuminated. The vehicle was taken to the local dealer, where it was diagnosed with a failure with cylinder five, no compression, and bearing failure. The dealer suggested the engine be replaced. The vehicle was not repaired. The contact indicated that the failure was related to the federal safety agency Campaign Number: 25V274000 (Engine and Engine Cooling) but was not included in the recall. The manufacturer was contacted who referred to the federal safety agency hotline. The failure mileage was unknown.

Filed Apr 28, 2026 · Engine · CT

Hello, I was driving on the highway with my family and my engine had a sudden loss of power. I only have 52,000 miles on the engine and it has been serviced the entire time. We almost got in a major accident as we had cars and trucks moving around us at a very high speed as we tried to pull over in the breakdown lane. I brought the car to Daddario GMC in Shelton, CT. They did a diagnostic test and said that cylinder 2 was misfiring. Upon closer inspection they saw that there was oil sitting on top of the piston head which indicates engine failure. I have since contacted GM warranty services given my car was just past the warranty date of November 2025, but still under the 60,000 miles of coverage. I did some research and have seen this is a very common with these engines as GM did a recall on 600,000 already. For some reason my VIN # is not listed on the current recall even though my engine is in the same year as the others that were. I would like GM to cover my engine 100% but was told they may only pay a % to fix it. Can you do anything to help me get them to cover the engine at 100%? I also wanted to let you know about this issue as my VIN was not under recall and this may happen to other people/families who have the same engine as mine that isn't recalled. Thank you, [XXX] INFORMATION REDACTED PURSUANT TO THE FREEDOM OF INFORMATION ACT (FOIA), 5 U.S.C. 552(B)(6)

Filed Mar 20, 2026 · Driver assistance, Engine · 110,000 miles · NC

The contact owns a 2021 GMC Yukon. The contact stated that while driving at various speeds, the vehicle shuddered abnormally with blue smoke coming from the exhaust, with the message "Lane Departure Assist" displayed. The check engine and stabili-trak warning lights were illuminated. The vehicle was taken to a local service center, where it was diagnosed with cylinder #1 misfire. The local dealer was contacted. The vehicle was not diagnosed or repaired. Upon further investigation, the contact related the failure to the GMC Service Bulletin:15-06-01-002L. The manufacturer was made aware of the failure. The failure mileage was approximately 110,000.

Filed Nov 24, 2025 · Engine, Fuel system · TX

I got 3 messages on the dash going off simultaneously 1. Service Traction Control System 2. Forward Collision System unavailable 3. Service ESC I could feel the truck bogging and shaking a little at this point Then soon after the check engine light was flashing and it was noticeably misfiring and rough idling. I pulled some codes at Oreillys and got back 1. P0300 misfire 2. P050D cold start rough idle