While driving home from work around 6 am, my car had multiple warning lights and warning messages come up all of a sudden. Immediately after that I lost my power brakes and steering and was not able to control my car at 40 mph. I was lucky the light I passed was green and there was no other traffic. I was able to bring my truck to a stop after more than a quarter mile by putting all my weight on the brake pedal. The truck was towed to the dealer and has been there ever since.

- Coral Gables, FL, USA

Driving down the highway the engine started skipping and started blowing out black smoke, and quit running in the middle of the highway. Found out the had a factory lifter defect on my model and a service update was supposed to be done on the truck changing out the lifters however even though I have gone to dealership for all the maintenance the service had never been done or told to me. This could have been very dangerous just engine failure the service by GMC N212353840

- Panama City Beach, FL, USA

I was operating my vehicle in northern Minnesota with a temperature well below freezing. Vehicle warning light came on that said "turn off vehicle" which I did. When I went to start it again it would not turn over. It appeared that a large amount of oil had expelled from the vehicle. It was very dangerous as I was in a very remote area with very poor cell service and extremely cold temperatures. I couldn't even run the vehicle to stay warm. The vehicle was towed to the nearest GMC dealership where they examined the vehicle and stated that the seal of the oil filter had blown off. They further stated that the oil filter which was installed by Valvoline was the wrong size. Valvoline tested the Champion oil filter and came back with findings that the filter was the correct size and noted no damage to the filter. Either there is an unknown problem with the GM engine or the Champion oil filter. Each corporation continues to point fingers at each others product.

- Ely, MN, USA

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 car sat in our driveway for over 2 weeks with a very potent smell causing headaches until GM and our insurance finally investigated. There is damage to our siding, driveway, landscaping, basketball hoop, trampoline, and neighbors fence. The car was only 2 years old and scares me how quickly it went up in flames and how much worse this could have been either 3 minutes earlier or if it was parked in our garage.

- Kirkwood, MO, USA

2021 GMC Sierra 1500 AT4 6.2L engine, Little over 39000 miles, Purchesed May 2021. This is the second time the vehicle has had this issue. The first time was aprox 15000 miles. I reported the issue to NHTSA-ODI on 6 Dec 2021 tracking # 11442943. I was driving down the interstate I heard a rattling coming from the engine (same as I had heard with the first issue). The check engine came on I ask On Star to do a digonsotic report (see attached report). The report indicated a Fuel Management System issue detected advised to reduce vehicle speed and pay load as possible. I was told by GM certified mechanics that this issue could cause the engine to lock up and come to a complete stop on the roadway. I fill that these vehicle are unsafe to operate under these conditions and may cause serious accidents. GM has known about these issues with these vehicles for several years and has failed to correct the problem.

- Pipestem, WV, USA

15000 miles lifter failure in traffic highway at speed 70 mph lost power engine failed multilane highway rush hour traffic no warning failure

- Plymouth , MI, USA

The contact owns a 2021 GMC Sierra 1500. The contact stated that while operating the vehicle, the dashboard gauges, instrument cluster, and infotainment center malfunctioned and became inoperable. Additionally, while starting the vehicle, there was a loud cranking sound coming from the engine compartment and the vehicle would not immediately start. The vehicle was taken to the local dealer, but the cause of the failure was not yet determined. The manufacturer was notified of the failure, but no assistance was offered. The failure mileage was 100.

- Honolulu, HI, USA

The contact owns a 2021 GMC Sierra 1500. The contact stated that while driving at an undisclosed speed, the vehicle went into Limp Mode with the check engine, DEF tank, and emission warning lights illuminated. The vehicle was taken to the dealer, and the dealer replaced several unknown sensors; however, the failure recurred. The dealer determined that the computer needed to be replaced. The vehicle was not repaired. The manufacturer was made aware of the failure. The failure mileage was approximately 35,000.

- Cartersville, GA, USA

Engine lifters failure, caused ESC light to come on and check engine light and other dash lights. Lack of power from engine causing dangerous driving in traffic.

- Fergus Falls, MN, USA

1 June 2022, while driving, started hearing a clicking noise from front end, under hood. Took to local GM dealer, Mechanic drove with me, and he heard the noise, said he would order a part and safe to drive. So, I went home. 2 June 2022 started same vehicle, a very loud banging, clicking, shuttering noise from under hood, I took back to same dealer, Dealer said collapsed valve lifter. GM service notice says for dealer to fix under warranty. Apparently, a known problem with MANY 2021 GMC 5.3 L engines. PLEASE MAKE GM RECALL THIS ISSUE FOR REPAIRDS

- Jacksonville, AR, USA

My truck shakes/shutters at random times. while steadily driving at constant speed and/ or shakes/shutters even more when I try to accelerate.

- Angelton , TX, USA

The contact owns a 2021 GMC Sierra 1500. The contact stated that the check engine warning light was illuminated and the vehicle failed to accelerate above 60 MPH. The contact took the vehicle to the dealer who diagnosed that the DEF tank had failed and needed to be replaced. The vehicle had not been repaired. The manufacturer was not made aware of the failure. The approximate failure mileage was 4,000.

- Gap, PA, USA

The contact owns a 2021 GMC Sierra 1500. The contact stated that after starting the vehicle, the check engine light remained illuminated and the vehicle would not properly accelerate while depressing the accelerator pedal. The vehicle was taken to the local dealer who diagnosed that the engine valve lifter was faulty and needed to be replaced. The vehicle was repaired. The manufacturer was notified of the failure. The approximate failure mileage was 11,000.

- Hot Springs National Park, AR, USA

While driving, when approaching speed of 40 mph, the engine begins to have dull shutter intermittently as though I am going over pot holes or rumble strips when I am not. Regardless of time or day or weather the truck has performed in this way. I have had it to the dealership twice for the issue. The first time they said they didn-??t feel anything and unable to duplicate the problem. The second time, the vehicle was with the dealer for several days trying to determine the other issue it was there for. I requested they again try to recreate the concern. The service assistance asked if I was willing to ride with the technician to see if I could point it out for him. In scheduled a time to do so, when I arrived, the technician was not there. I reside an hour away from the dealership. Making these round trips and getting no where with support or answers. When this happens, I become extremely anxious about the safety of the truck. Also- while 4 X4 is engaged, the truck has significant shutter when going up hill, as though the transmission is going to drop. The entire truck will violently shake.

- Hanoverton, OH, USA

Vehicle has less than 10,000 miles. Started making a loud noise and shuddering in the engine while at speed on the highway. Made it to dealer but was concerned we were going to break down before making it safely there. Service manager strongly suspects engine lifters (he drove it briefly with me and says this is a known issue with this truck & they currently have 3 other trucks in the shop with this same problem. He said parts are a 3-4 month wait and vehicle is not driveable, will break down, but couldn-??t say when - could be 10 minutes, an hour, or a day. This happened to me on 2/1/22, while out of town on vacation. An hour on the phone with GM and was passed around to 3 different individuals. GM would not provide a loaner vehicle - leaving me stranded out of state. I had to get a rental vehicle on my own, GM claims they will reimburse me for a portion of this after 6-8 weeks. GM will not tow the vehicle home to Virginia (vehicle is in NC). I had to turn in rental car once I returned home because I can-??t afford to keep paying for this on my own and it-??s not a truck, which I depend on. Dealer is unable to fully diagnosis and document until end of week 2/7 or early week 2/14 as they are very busy. Unacceptable on ALL levels.

- Gainesville, VA, USA

8 lifters in my vehicle needed to be replaced. While driving my vehicle (12/4/21), after the auto stop feature was activated my truck experienced a lack of power and hesitation. I then turned the truck off and upon starting it was making a knocking noise. I immediately checked the oil as I wanted to make sure there was oil in the engine. I had warning lights on the dashboard and drove it about 3 miles to the dealer to be repaired. While driving it to the dealer, it did not sound right and shook. I also experienced a lack of power and was concerned for the vehicle to stall out while in traffic. The dealership informed me this is an issue with the 2021 GMC Sierra with a 5.3L V8 engine. I had seen online that GMC issued a service bulletin to have the lifters replaced in the 2021 GMC Sierra that were on the lot before they were sold (early December 2021). If this is a known issue why weren't the lifters replaced in vehicles on the road before the ones sitting on the lot. 8 lifters were replaced by the dealership but there was a shortage of parts due to the nationwide problem. There were no warning lamps, messages prior to the failure. The only symptoms I had was shaking and lack of power as indicated above after the autostop feature was activated. I then drove about 2 miles and went into a store before coming out and having the loud knocking on startup followed by warning lights and messages.

- Saegertown, PA, USA

Can turn vehicle off while in gear (drive specifically). When you let off the brake, the truck acts as if it is in neutral. Discovered in my driveway when accidentally forgot to shift into park when I pulled in and pushed the stop button. Truck turned off, which would only expect if in park (or neutral), let off brake, and it began quickly rolling backwards as if it was in neutral. Fortunately the brakes were working, but had any children been riding a bike on the sidewalk or walking by, my truck may have hit them. Had I been more distracted and not noticed initially, it could have rolled into the road and hit my neighbors truck. This behavior can be reproduced every single time, and I can easily supply video.

- Lithia, FL, USA

Less than 300 miles on the vehicle and it has thrown an error code P2B60. Relating to the engine coolant flow control valve position sensor. I have taken it to my local GM service center and they cannot see me for weeks. As of this morning the check engine light has disappeared but my fuel economy has severely decreased. It seems suspicious and possibly dangerous that it showed a check engine light with a warning of reduction in engine power the night before and disappeared in the

- Canton, GA, USA

Famous lifter issue in the l84 engine. Hundreds of documented complaints and current class action lawsuit. I had to stop on a busy highway and it caused unsafe passing and irritated humans.

- South Haven, MI, USA

On 11/19/2021. While on the express way our truck started sounding really bad. We drove it slower to a gm dealer in Highland MI. They said we had a misfire. And there was nothing they could do at this time. We drove a little further and it got worse. We had to stop at a rest area. After dark and in the freezing weather. We had it towed to a dealer in Frankenmuth MI. Our truck has 11,800 miles. It has a diagnostics report of Valve lifter defects left bank. Starter had to be replaced. And now gm wants to only fix to affected bank. But on the unsold trucks they will repair both banks as stated in service bulletin N212353840. If we have one bad lifter they should all be replaced as for this not to happen again. As of 12/08 2021 it is still in the shop [XXX] Thank you INFORMATION Redacted PURSUANT TO THE FREEDOM OF INFORMATION ACT (FOIA), 5 U.S.C. 552(B)(6).

- Pinconning, MI, USA