2020 GMC Sierra 1500 Fuel System Problems

Owner reports

Selected complaints filed with NHTSA by 2020 GMC Sierra 1500 owners, lightly cleaned up (personal details are redacted by NHTSA).

The fuel pump module failed according to the dealer at 34000 miles . Car stop while driving. Cranks but no start. After resting it for hours I was able to start. Drive couple of miles about 39000 miles it stops middle of driving and couldn't start anymore but still cranks

Fuel Pump Drive Control Module (Part No. 13540028). This item is a recall on several other vehicles, but not identified on my year/model. On 4 separate occasions over a 3-4 week period, the engine starting running very rough lost power and stalled while traveling down the road (highways, interstate, and a side street). I was finally able to pull a fault code and research the history of this code and this part on several other GMC/Chevy modeled vehicles. The dealer advised I was lucky to find the part because most of them are on backorder due to the recall on other vehicles. The one I got was for a recall, but the customer hadn't returned in time so they sold it to me. I had a repair garage replace the component on Jan 13, 2024, and haven't had any repeat issues. The check engine light did come on each time with a P129F code. …

2020 GMC Sierra Denali - VIN [redacted] On [redacted] while driving the 2020 GMC Sierra to work I noticed a strong gasoline smell inside the cabin. I immediately returned home and parked the truck in the street. Inspecting the driveway where the truck was parked over night, I notice large gasoline spot. The following day I had the truck towed to Boyds Tire & Service center to have the truck inspected. On January 20 Boyds called me and shared the truck had experienced a failure of the High-Pressure Fuel Pump which has been recognized by GM as a recall under N192283991. I called a local GMC dealership about this failure and they stated it would cost $300 to review and would not perform any work under a recall. Also, the dealership stated they could not service the truck for another two weeks, which I cannot be without the truck that long. So, I had Boyds perform the repair the same day. …

1. The vehicle's emissions system is malfunctioning, specifically the ECM (Engine Control Module) related to the exhaust emissions system. The diagnostic trouble code is P2C7A, indicating the system is not performing as expected. Key components such as the NOx catalytic converters and diesel particulate filter have been repeatedly replaced, but the issue persists. The vehicle and all replaced components are available for inspection upon request. 2. The malfunctioning emissions system has led to an exhaust leak that allowed exhaust gases to enter the vehicle's cab. This creates a hazardous environment for both the driver and passengers, exposing them to harmful exhaust fumes. In addition to reduced engine performance, poorer fuel economy, and emissions non-compliance, this exhaust leak poses a serious safety risk by compromising the air quality inside the vehicle. …

I again have noticed intermittent pulsing at low to medium speeds. At roughly 1k-2k rpm the engine at or about 10-20 mph is pulsating or hesitating with an obvious pulse which you can see on the tachometer as well (bouncing.) It seems like there is either a computer, fuel flow or electric issue. Also, at speeds up to the 40 mph range, this is happening as well. Yesterday while towing a small 7'x12' empty dual axle trailer I noticed it again, I occasionally use my trailer to haul small loads up to 4500lbs. This has happened before but this time I decided to notate this on your site, since reading about ongoing problems with the 2020 6.2L GMC Sierra 1500. I was aware of the other following years, 2021-2024? issues and that is why I purchased this 2020 year model. My truck will be available for inspection when the request is sent to me. …

Vehicle: 2020 GMC Sierra 1500 SLT VIN: [VIN] Engine: 6.2L V8, RPO L87 Mileage: approximately 129,854 miles My 2020 GMC Sierra 1500 equipped with the L87 6.2L V8 experienced an engine failure and has been diagnosed as needing an engine replacement. I am reporting this because my vehicle is equipped with the same L87 6.2L engine currently being investigated by NHTSA under Engineering Analysis EA25007 for engine failures occurring outside the scope of Recall 25V-274. My model year is not currently included in Recall 25V-274. However, EA25007 specifically addresses L87 engine failures occurring outside the existing recall population, including 2019-2024 GMC Sierra 1500 vehicles. …

I was about 45 miles or so from home on [redacted]. As I left a business my truck went about 100 feet and the engine stopped working . No warning. Truck was towed to a GM dealer in Wilmington Il. It was determined the cause was due to the wiring from the engine ECM that was run over the top of a very sharp plastic mounting bracket for the ECM. The wire had been cut because of the way this was done at the factory. In addition the fuel pump also needed to be replaced . At the time of this, the truck had 39,140 miles on it. I had no warning this was about to happen. No check engine light went on , etc. Most of my route home is on the highway . Had this not happened on a side street , I would have been involved in an accident. I ended up paying $865.42 plus towing for this repair I should not be paying for. …

Shuttering while in motion at a speed of 35mph or above. My 2020 GMC SIERRA 1500 AT4 CarbonPro while driving at or above speeds of 35mph experiences a hesitation and severe Shuttering while trying to maintain any speed of 35mph or above. The hesitation causes extreme vibrations and hesitation when lifting or applying foot to the accelerator. This happens in any drive mode also with cruise control on or off as well as shifting into low and being in any gear trying to prevent it. It also does this on any road and condition. It feels like a slip in the transmission or torque converter, possibly could be the rear end or variable valve timing as well. And when taking of from a red-light or stop sign it slips as if the truck has lost traction, but it hasn't. This is very dangerous and could be the cause of a serious accident when trying to accelerate. …

I had Engine Failure in June 2024 with roughly 50,000 miles. I was getting on I75 North in Auburn Hills, MI, when I heard a loud pop. The vehicle began shaking violently with a loss of engine power warning displayed, loss of oil pressure displayed followed by 2 successive limp mode warning. The vehicle would not drive over 25 MPH. Luckily the next exit was only a mile down the road. I was able to drive on the shoulder of the Interstate to get off of the highway. When I parked the vehicle shortly after, I viewed oil spewed all over the engine bay and under the truck. I then waited 4 hours in 95+ heat for a tow truck. The engine was replaced by the dealer with no root cause identified or communicated to me. There were no warning prior to this failure. …

I started to notice changes in performance around 75k miles. Seemed like performance was subpar compared to what was the norm. Seemed to lose some power. Minimal at first, more so just recently around 90k. Oil consumption was starting to accelerate at each oil change at 75k, 80k, 85k, 90k. To the point around 85k and 90k that I would not go over even 1 mile from the 5k threshold without changing the oil. Around 90k I could tell it was not getting any better, deficiencies were accelerating it seemed. At 91k miles I started to hear clicking noises and loss of power, starts were getting rough, bouncing at idle. I stopped driving it, only driving it to the dealership where I brought for a look at it. Will be driving it again for them to do a deeper diagnostic. Many misfires at cylinder 5. PO305 the issue. Showed up around 91k miles on 12/17/25 Now investigation into my model. I see online.

Related recalls

Fuel System complaints in other Sierra 1500 years