2021 GMC Sierra 1500 Fuel System Problems

Mileage when the problem started

Owner reports

Selected complaints filed with NHTSA by 2021 GMC Sierra 1500 owners, lightly cleaned up (personal details are redacted by NHTSA).

Less than 5 minutes after my husband and 2 children parked the car and came inside, a neighbor walking rang our doorbell to let us know there was something on fire in our driveway. We ran to the back to find his truck engulfed in flames coming from the engine. We quickly called 911 and exited the house/property. The truck continued to burn with 20-25 foot flames and very black smoke for about 40 minutes until the fire department was able to control the fire. The fire was hot enough that the entire engine was significantly burnt, the seats and steering wheel were gone, the glass shattered and melted, and the tires exploded and melted. Thankfully, everyone was out of harms way and safe through this incident. However, it has been extremely traumatic on my family and neighbors and has taken a lot of time and energy to try to deal with this. …

The contact owns a 2021 GMC Sierra 1500. The contact stated that after driving on a trip, the contact noticed that the vehicle had lost 10 MPG after a software update was performed. The check engine warning light was illuminated. The vehicle was taken to Richardson Chevrolet (3825 S Huron Rd, Standish, MI 48658), who confirmed that the vehicle was working as designed. The check engine warning light was reset. The vehicle was not diagnosed or repaired. The manufacturer was contacted and opened a case, and referred the contact to the NHTSA Hotline for assistance. The failure mileage was approximately 57,000.

I was driving on the freeway and my gmc Sierra at4 received a notification that I could could no longer accelerate. I pulled off to the side as safely as I could in a slanted hill in a major freeway with no shoulder. I sat on the side of the road for 45 min and then ran out of diesel gas waiting for the tow truck. We took into gmc and they said nothing was wrong, we were out of gas. But I ran out of gas waiting for the tow truck. The truck never shut off and ac still going, I just couldn't accelerate. We've had the truck in the shop every single month for the past year for sensor issues and replacements and have all the documentation of the last few years of similar issues. No extensions of warranty's nothing. Well we started to smell something burning this week and now we were told today we have a faulty fuel pump that will cost us $1,000 to fix and is not covered under our warranty. …

I am an active U.S. Air Force member. My 2021 GMC Sierra 1500 failed GM Recall N252494003 on Sept 29, 2025 (L87 engine loss of propulsion). GM states this defect can cause sudden engine failure and loss of propulsion, increasing crash risk. Despite the confirmed failure, Ocean Cadillac (Miami, FL) told me to keep driving the unsafe vehicle and refused all Courtesy Transportation. The Service Manager admitted in writing that the engine failed, the defect can cause loss of propulsion, and the replacement engine is delayed under GM National Control for up to 3 months - yet they still denied me a loaner or rental. His statements contradict the GM documents he attached: GM Bulletin DCS7222 says Courtesy Transportation CAN be provided during L87 recall downtime and dealers MUST consider loaners/rentals. GM FAQ N252494002 says Courtesy Transportation IS available for this recall. …

Engine developed a low knock type noise just above idle while beginning to move in the parking lot. It was also noted pulling away from an intersection at low rpm under light acceleration. Oil pressure was normal, 30 psi and approximately 50-60 at cruising speed. Low level knock began earlier in the day but no other symptoms. Oil level was checked and found to be at proper level. At mile 2 into my trip a chirping/ squeak type noise was heard under light throttle and light load at approximately 1500 rpm. The noise stopped when accelerator was released. Rough running sensation followed the noise under the load. Noise returned when the accelerator was pressed and then the engine stopped running while traveling 45-50 mph. Placed the shifter to neutral and attempted to restart, engine rolled slowly for a brief moment and then locked up entirely. Starter only clicks when attempted after that. …

On [redacted], my vehicle suffered a complete loss of propulsion on the highway, displaying fault codes P0324 and P0016. The vehicle was taken to Boyd's Tar Heel Chevrolet in Roxboro, NC, where the engine block was replaced under the official GM 6.2L engine safety recall.The truck was delivered back to me, and on the very first day I drove it-only 28 miles from my house-it suffered a secondary catastrophic loss of propulsion on the highway on [redacted]. The check engine light began flashing violently, indicating an immediate catalyst-damaging safety hazard, and the vehicle displayed fault code P0307 (Cylinder 7 Misfire).The dealership explicitly instructed me to stop driving the vehicle immediately, authorized the recovery, and told me to bill the tow directly to them. After towing the vehicle back to their facility, Boyd's Tar Heel Chevrolet reversed their position. …

While driving into work, I noticed a knocking sound from the outside of the vehicle. Once parked, upon further inspection I narrowed down the area of the noise to the bottom rear of the engine/front of transmission. Fortunately, I was able to park in front of my office building and wasn't stranded on the side of the road but under different circumstances it could've been the side of a busy highway or hours from home. I had the vehicle towed to the dealership I originally purchased from, the dealership was able to duplicate the issue with me present. Later that afternoon I was informed that the engine had failed and a replacement would be ordered. There was no prior indication of a problem or warning/CEL's. The engine failed after the dealership had completed the engine recall ( pico test and 0-40W oil change ) related to the vehicle. …

So I made an appointment to have my truck recalled and the Wednesday before I took it, and it cranked no start and I called the dealership. Ask if they had any other those like this and they said that it could be the fuel injector module and so I got it to a mechanic shop to read the codes and it gave me a code p062b and I asked the dealership to look into it and they never figured out what we were not wrong. I just testing the battery. Well, then I got it back after the recall was done and new transmission valve body put in and about 30 miles down the road it started to shake violently and had a flashing engine light so I got it home called the dealership the next morning because they were closed set up another appointment got it to the dealership dealership said it had a couple misfires but since it wasn't over 100 they weren't concerned even though I'm pretty sure it is related to …

2021 GMC with 6.2L motor. The engine begin to produce a clattering noise in the upper part of the engine. When the clattering happens the vehicle will shudder. I took the vehicle into a certified independent service center who diagnosed a catastrophic engine failure as a result of lifter and camshaft bearing failure. They further advised that this year of vehicle (2021) and engine (6.2L) was known to have this defect and might be subject to a safety recall. I contacted GM customer service who stated that my VIN was not included in the recall even though the year and engine matched the recall. I found that to be odd especially when I noted that nearly 600K vehicles matching my failed engine was recalled. She stated that I (owner) had to bear the cost of replacing the defective engine and labor. I had to have my vehicle transported from [redacted] to [redacted] at the cost of 1400 dollars.

After having simple oil and filter, and engine and cabin filter replaced at Alpine Buick GMC in Colorado Springs, CO, I received my vehicle back and noticed a complete difference in performance. It hesitates when accelerating, stays low in every gear, and bounces, and I mean bounces hard, when shifting gears, especially slowing down. When slowing down, as it shifts to the next lower gear, it almost pushes the truck forward against me pushing the breaks. Then, when feathering to accelerate slowly, it almost bounces back up to speed, hesitating until I let off the accelerator pedal a little, and it immediately shifts to about 1000 rpm in gear. I have to push really hard for it to go up a gear, and when it does, it has lost all power. My vehicle doesn't run right anymore after my service appt. I have brought it to my hometown dealership and they say it runs fine and nothings wrong. …

Fuel System complaints in other Sierra 1500 years