2020 GMC Sierra 1500: sudden loss of power

Filed Oct 7, 2026 · Engine · NY

While driving down interstate noticed drop in oil pressure and immediately a noise in engine with loss of power. immediately took it to dealership and they diagnosed rod bearing failure. Gm refuses to pay for engine.

Filed Oct 5, 2026 · Engine · NC

My 2020 GMC Sierra 1500 SLT with the 6.2L L87 engine experienced complete engine failure at approximately 129,000 miles. The vehicle is currently at Trent Cadillac GMC in New Bern, NC and is available for inspection upon request. The dealer confirmed the engine requires replacement along with timing-chain-related repairs, estimated at approximately $11,000. Before the failure, I had previously reported concerns involving oil pressure/engine operation to a Chevrolet dealer. At one visit, the dealer documented that it could not duplicate the oil-pressure concern. The vehicle was later serviced again, but the problem ultimately progressed to complete engine failure. When the truck arrived at Trent after the failure, no oil registered on the dipstick. This presents a safety concern because sudden engine failure and loss of power can leave a driver unable to maintain normal vehicle operation or safely exit traffic, particularly at highway speeds. After the failure, the truck was evaluated by Big Boys in Grimesland, NC and then towed to Trent Cadillac GMC for authorized GM dealer diagnosis. GM Customer Care has also reviewed my case. I am concerned this failure may be related to known failure patterns involving GM 6.2L L87 engines and internal engine components. Although my 2020 model is outside the current recall population, it experienced complete engine failure after earlier oil-pressure concerns. I am requesting this failure be documented and evaluated as a potential safety defect, including whether earlier-model L87 engines may experience similar failure mechanisms.

Filed Oct 2, 2026 · Engine · 124,000 miles · NY

The contact owns a 2020 GMC Sierra 1500. The contact stated that while driving 74 MPH, the vehicle made a loud banging sound, reduced engine power, and was losing oil pressure. The dealer associated the failure with the federal safety agency Action Number: EA25007 (Engine, Engine and Engine Cooling). The dealer was contacted and the vehicle was diagnosed with rod bearing failure. The manufacturer was contacted by phone and made aware of the failure. The failure mileage was approximately 124,000.

Filed Sep 14, 2026 · Engine · 115,000 miles · MN

The contact owns a 2020 GMC Sierra 1500. The contact stated that while driving approximately 55 MPH, the vehicle started losing power and decelerated. The check engine warning light was flashing with several unknown messages displayed. The vehicle was parked on the side of the road and later towed to the local dealer to be diagnosed. The contact was informed that the lifters, push rods, and camshaft had failed and needed to be replaced. The lifters, push rods, and camshaft were replaced, and the vehicle was repaired. The contact stated that approximately 6,900 miles later, the failure reoccurred. The vehicle was towed back to the local dealer, and the contact was informed that the engine crankshaft and connecting rods had failed and the engine needed to be replaced. The vehicle was not yet repaired. The failure mileage was 115,000.

Filed Aug 6, 2026 · Engine, Transmission · IN

"While driving, the vehicle suddenly experienced a flashing check engine light, an Electronic Stability Control (ESC) warning light, and violent steering wheel vibrations. The vehicle suffered a severe loss of power and misfired, creating an immediate traffic hazard. The dealership diagnosed the issue as a catastrophic mechanical lifter failure on the 5.3L V8 Ecotec engine with Dynamic Fuel Management (DFM). Despite the dealer replacing an entire bank of lifters, the engine continues to misfire and vibrate. This premature valvetrain failure at only 36,000 miles is a known design defect that causes sudden engine stalling and disables critical safety features like stability control while the vehicle is in motion, presenting a severe crash risk."

Filed Jul 17, 2026 · Suspension, Transmission · MD

My truck transmission beed jerking off and on for over a year. One time it lose power when i was driving and could have caused an accident. I took it to the dealership and they said i new a new transmission for $12000. Something just doesn’t seem right about this! I brought a brand new truck thats unsafe and its no recall for my model but other models with the same issue had a recall. I would just like some answers. I feel like i brought a lemon. Thanks for listening.

Filed Jun 23, 2026 · Engine · IN

My 2020 GMC Sierra 1500 Denali with L87 6.2L V8 suffered a catastrophic, silent seizure at 108,000 miles. Driving at highway speeds, warning light stating shift to neutral and press start, engine completely shut off and would not turn back on. I was in the car with my 3 children about to make a turn across a 4 lane highway. I was able to recognize that there was power loss quickly enough that we were safely within the turn median, and fortunately a "good samaritan" stopped to assist us in getting across the highway into a parking lot. I hate to think what would have happened had this power loss occurred during the turn. There was no warning light, sound or other issue prior to this occurring. The vehicle has been meticulously maintained with all services occurring at my local GMC dealership. We had the truck towed to the dealership who confirmed the engine needs to be replaced.

Filed May 23, 2026 · Engine · NY

Good evening, I want to formally document what happened today regarding my GMC Sierra after I brought it to the dealership on Friday morning for transmission concerns that I had already reported. At that visit, the vehicle was inspected, and I was informed that the truck was still safe to drive while waiting for the extended warranty approval for the replacement parts that were needed. Unfortunately, today my family and I experienced a very serious and frightening incident on the expressway. While driving, the truck suddenly lost power, barely moved forward, and began shaking violently. We were placed in a very dangerous situation in traffic and struggled with great difficulty and fear just to make it home safely. Once we arrived home, the vehicle completely shut off and would not restart again. This situation was extremely alarming, especially because I had already reported the transmission problems and trusted the guidance given to me that the vehicle was still drivable. My family’s safety was put at risk, and I need this matter to be treated with urgency and seriousness. Please advise immediately on the next steps regarding the vehicle, towing assistance if necessary, and how this situation will be properly addressed. Thank you.

Filed May 20, 2026 · Steering · OH

A known problem with these trucks is ground strap failure. I was driving and all the sudden lost power steering which almost caused an accident. There is a customer satisfaction program N252515590 that covers 2019-2024 trucks but mine was not included in this for some reason. I did have the truck fixed a my cost and was looking to get my money back from GM. I'm not sure if you can help with this but wanted to make a report that is happening with more trucks then they are fixing. If you need any other info from me please let me know

Filed May 18, 2026 · Engine · MS

Sitting at a red light and when the light turned green, the engine made a noise and lost power while trying to cross the intersection. The check engine light came on along with some other lights. It was then towed to a mechanic and the engine had to be replaced due to failure of the lifters. The mechanic said it is a common issue with the GM 5.3 engine but unfortunately their has not been a recall.

Filed Apr 24, 2026 · Engine · MI

My 2020 GMC Sierra 6.2L (only 46,000 miles which is under warranty mileage criteria), suffered catastrophic engine failure while at 40 miles per hour out of no where and rolled without power for about ~60ft. Power came back on, and I was able to get closer to the dealership but again, lost all power and rolled for about 60ft again right in front of the dealership. The truck died while attempting to make a left turn (in oncoming traffic), it got going again in time to finish the turn. When I pulled into the dealership it pulled code P0016 which is the same code for the 2021-2024 recall currently for the 6.2L GM engine. I had all oil changes completed on time and can show evidence of them. Other repairs, recalls etc were completed at the GMC dealership. The 2020 Sierra 6.2L should absolutely be included on the GM recall. Same issues as 2021-2024. Funny how 2020's just reached over on time limit for warranty. The repair estimate for my truck is over $13K!!!

Filed Apr 13, 2026 · Engine · OH

There is a click/ticking noise when vehicle is started. Noise gets louder and faster when accelerating. Have taken vehicle to 2 mechanic shops and been told by both places it is bad lifters and exhaust manifolds. I took this truck in because of loss of power. This issue has put me in unsafe/ dangerous positions on multiple occasions.