-Engine gas consumption states 21 MPG Highway, 17 MPG combined and 15 MPG City. -When I started using vehicle during the first weeks and months the best MPG I could geta at the highway was 18.5 MPG with top-tier gas. -Ever since I bought the vehicle, the gas MPG have gone down around 0.5 MPG. The vehicle feels that it has to use more gas in order to perform the level of task everyday. -The motor oil pump at times moves down from the 40 mark to the 20 mark when idle at traffic light and it starts moving, it temporarily goes to the 60 mark. At other times when idle it stays in the 30 mark. -The transmission is an 8 speed automatic. It has issues shifting 1st and 2nd gear, and at times 3rd gear as well. When driving at slow speeds like in a traffic jam, mall parking, do a u turn or when you slow down at the traffic light and then turns green and you start accelerating again it feels harsh on gearing up and down. -This vehicle has the Active Fuel Management (AFM) system, it turns on even at slower speeds and you feel how the engine and transmission struggle to accelerate, go a gear up and push the vehicle with only 4 cylinders. Like in manual transmissions when you accelerate on a higher gear than the correct one, it takes forever to accelerate and properly change to 8 cylinder and establish the correct gear and ratio. -Even if all 8 cylinders on it it feels like if I am running on a smaller engine. -There was a fix done to the transmission for a valve, but the vehicle still runs the same as before. -There is a knocking noise starting to build in the engine. Best mileage I can get driving the same and gas is 13 MPG combined. -The recent safety recall for the breaks is actually making the breaking worse than before. -My vehicle is 2016 GMC Sierra All Terrain V8 5.3L 4WD Z82 with 36,500 miles on it and is doing all this and its getting worse little at a time.

- El Paso, TX, USA

At very low speed, my brakes fail. They work fine at regular speed. It-??s only when I am parking or like at a drive thru. I almost hit someone.

- Alice, TX, USA

Brakes at low speeds and in drive ways and parking lots when stopping brakes won't work very dangerous a recall was issue but not for my truck, the vacuum pump is bad on my truck

- Bakersfield , CA, USA

At slow speed the brake becomes rock hard and cannot be pushed in. I have researched a recall # N192268490. I have searched my vehicle by VIN and it states no recall which I don't understand. I believe it is something related to the slow speed brake module. I would like to know if this is an actual recall and why this vehicle is not included.

- Hampstead, NC, USA

"service brake assist" message has continuously shown up on dash for over a year, especially while at low speed in reverse most commonly. Vehicle feels like power brakes no longer function and vehicle continues to roll unless you stand on the brake pedal. This is supposedly after the recall repair.

- Flanders, NJ, USA

Brake assist light came on and I had no brakes when I pushed the pedal harder brakes tried to lock up I almost wrecked

- Port Saint Lucie, FL, USA

Mipowered brake-assist system, which reduces the amount of effort a driver needs to exert to stop the vehicle. If the system fails, a driver may find that the brake pedal takes much more effort to push. Drivers may also find that it takes more distance for their vehicle to stop, which could lead to a crash,

- Wappingers Falls, NY, USA

The brakes are very hard to press at low speed more so after I have pressed them a couple times or more while in motion in stop and go traffic. I had a recall for this about a year ago and took it to the dealer to have it fixed but just started experiencing this problem within the last couple of months. Very scary to not have power brakes all of a sudden! the recall obviously does not fix the problem!!

- Yadkinville, NC, USA

When traveling backwards at low speed it appears that my ABS is trying to turn on. The light doesn't come on, but it is very hard to stop. It will do it going forward, but mainly backwards.

- Johnstown, OH, USA

While moving slowly in traffic (~5mph) when applying light brake pressure it felt like ABS was kicking in and there was no braking. This happened twice before the brakes resumed normal operation. Happened again as I was backing out of my driveway. The recall regarding the reprogramming of ecbm (N192268490) was done already.

- Hebron, KY, USA

Brakes fail. Will not allow vehicle to come to a complete stop when going forward or in reverse. When accelerating vehicle violently shakes. This happens at any speed above 20mph.

- Goose Creek, SC, USA

At low speeds the brakes get very hard to press and the truck takes longer to stop. The service brake light has came on sometimes when this occurs. I've seen an open recall for the exact problem with my truck, but when I enter my VIN it says my truck is not part of the recalled vehicles. Please help

- West Monroe, LA, USA

Brakes became spongy while hauling a boat almost crashed while coming to a stop at a traffic light brakes were hard to compress. Vehicle didn't want to stop immediately... had to use the emergency brake to come to a complete stop. Right after the service warning sign came on showing ( brake assist service)

- Barrigada, GU, USA

At startup, if you shift from park to drive or reverse, the brake pedal stiffens and it is hard to stop. If you are able to speed up over a certain speed, say 15 to 20 mph, then the truck brakes fine. I have taken it to the dealer and they replaced the brake booster pump, but it started doing it again within a day or two.

- Flower Mound, TX, USA

I bought my GMC brand new with 25 miles on it. The first time I had a braking issue was pulling into work. I had roughly 56,500 miles on the truck at this point. I was coming in cautiously due to a heavy traffic area. As I pulled into my parking spot I engaged the brakes. The pedal was softer than usual. I pushed down harder and I came to a slow rolling stop. I thought I was going to hit the building. I let the truck sit/run 5min, (I am mechanically inclined, was in automotive tech courses for 3 years) I checked the brakes/brake fluid and tried the brakes in the reverse gear. Let the truck creep back and tested the brakes. They were normal again. I called the dealership and made an appointment.(uploaded service paperwork). Dealer said there wasn't a recall at this time but wanted me to do a brake fluid flush but I wasn't in warranty anymore so it was going to cost me over 100+ dollars. That's why I refused the service. The winter months go by and my brakes are fine. The second time I noticed this issue, was spring time the following year, I was putting my pontoon boat in the water. Backing into the water I went to stop and my truck kept rolling into the water. I engaged the emergency foot brake. I pulled forward and the brakes were back to normal. I test drove the truck in the empty parking lot this time, see if it would happen again. Called the dealership and asked if there was a recall and they said no. Brakes are back to normal at this point. Finally that year I received a recall notice in the mail. I went to the dealership completed the recall. I thought everything was fixed. Apparently not. I was stuck in a traffic jam at a slow roll, braking more frequently and the pedal went soft and to the floor again. I almost hit the vehicle in front of me. I stopped just in the nick of time. I am now currently working with the dealership to get this brake issue resolved.

- Edwardsburg, MI, USA

At very low speeds such as backing up or parking the brake pedal will not indicate pressure as if the truck was shut off. While backing up or parking you may hit another vehicle. This has happened more than a few times and we returned the truck to have this condition corrected. GMC dealer said it was a recalled for that issue and it was corrected but it seems to have returned.

- South Windsor, CT, USA

While backing out of a parking space, I lost the ability to depress the brake pedal. It was stuck momentarily. It only move after I stomped on it twice. Afterward, the vehicle would stop, but the brakes were squishy and very easily over applied. Service brake control message is now on the dash. Truck has 42000 miles.

- Maribel, WI, USA

Driving on the highway brakes locked up break pedal super hard to press

- Gilroy, CA, USA

I was driving my down a 4 lane highway and when I went to stop I had no brakes and rear ended a vehicle. My break peddle went to the floor.

- Monroe, NC, USA

When braking the brake paddle gets hard and does not allow me to brake. Thankfully it has happen only when I am parking or coming to a stop. Less then a month ago I took it in to our local GMC dealer and in half an hour they said it was fixed. A few days ago it happened again and went back to local dealer and customer service said they can schedule me in two weeks to fix the issue. I don't feel comfortable driving when it's a brake issue I believe it should be fixed or at least try to fix the issue as soon as possible not in two weeks.

- Salinas, CA, USA