Beginning in 2018, perhaps earlier, I noticed that often when I would press the accelerator all the way, the engine would (and still does) make a sound (I-€™ve since learned, through many dealership interactions and internet searches, that the sound is referred as pinging or knocking from pre-detonation), and it SEEMED that the car-€™s computer would (and still does) electronically back off the throttle, and the rpm-€™s reduced in terms of speed of acceleration (sometimes the rpm-€™s even DECREASED as opposed to merely increasing less rapidly). This has placed myself and passengers of the car in danger by causing the car to go through intersections significantly slower than I (as well as my mother who also occasionally drives the car) would naturally anticipate, as this slow crossing through the intersection has led to many close-calls when intersecting traffic (when they have the right-of-way) almost crash into the broad side of the truck. It USED to occur I would put in any fuel with an octane rating lower than 91, but now it even happens with 91 octane fuel. The problem has been reproduced by two Chevrolet dealerships. I have taken it in many times to have them repair/replace/service parts that I thought might be causing the problem. The shop foreman at one location replicated it and said he had no idea what the cause could be. The service dept. was then in back-and-forth contact with engineers at GM over the next couple of days, and the engineers eventually suggested an oil system flush thing (which ended up not helping). It-€™s had oil filter changes, fuel induction service, and basically everything short of replacing the injectors or pistons. Neither the vehicle nor its components have been inspected by the manufacturer, police, insurance representatives or others. No warning lamps or messages have ever displayed in relation to the problem. My co-worker-€™s husband has a 2018 GMC Canyon with a V6, and says the exact same thing happens with his car.

- Eagle Mountain, UT, USA

Just purchased vehicle in early March of this year(2022).Vehicle has low mileage for a 2015.But first problem is an air or evap problem that seems to be a large problem with other owners as well.Unable to fill vehicle with fuel pump nosil without it splashing out of vehicle.Came out on my shoe the first time!!You have to let it trickle into tank to get gas in it.Had it at dealer 2 weeks after i bought it to have a active un-related recall done, so I had them look into the filling problem.They replaced a part that said was bad(evap solinoid)that didnt fix fueling problem, and costly to remove tank to search for problem, going to fix myself.Find it hard to believe that this isn't a known problem.Second is a technical service bulletin from 2016, NHTA #101137960, Manufacturer #16-NA-195.This should be a recall and checked to see if repair has been made.I assume this won't be covered on my vehicle so I will have to fix fuell leak, truck only has 74,000 miles.This fuel leaking could be potentially dangerous, it's happening while your filling as well, would only know it unless you looked way under vehicle.Heavy fumes is bad as well.With this "technical bulletin"things you haul could drip and leak onto fuel tank so beds should be sealed to keep this from happening regardless!!

- Columbus, OH, USA

The contact owns a 2015 Chevrolet Colorado. While driving various speeds, the vehicle hesitated and would not immediately accelerate. In addition, the check engine indicator illuminated and the odor of fuel was present inside the vehicle. The vehicle was taken to the local dealer (Chevrolet of wasilla, 3700 E. parks hwy, wasilla, ak), but the cause of the failures were unable to be determined. The manufacturer was notified and did not assist. The failure mileage was 45,000.

- Kenai, AK, USA

My 2015 Colorado Z71is experiencing moderate to severe hesitation concerns. It's progressively getting worse. I first brought it back to the dealership to have it checked out around1000 miles, 6000 and now 20000. Each time they claimed they can't do anything because the diagnostics reveal no trouble codes, although, per aforementioned bulletin, there's proof that a problem exists. I inquired if it could be a mechanical issue, but they refused to because no diagnostics produced no codes/proof.

- Alexandria, VA, USA

Engine stalls intermittently when beginning to accelerate from red light/stop sign. Stalls occurred within 1 mile distance from where vehicle was started. First stall was at red light moving forward lightly. Sifted the vehicle to park, turned key, vehicle turned over and was able to drive once put in park. The vehicle was immediately taken to the Chevy service center. The service advisor was able to read an error code P0506 even though the check engine light was not illuminated. Chevy could not schedule an appointment for the vehicle until 5 days later; the error had cleared and they were unable to duplicate the problem. Service department declared vehicle safe to drive as it the issue couldn't be duplicated. Engine stalled a second time when beginning to cross road at a two-way stop with oncoming traffic. Shifted vehicle to park, turned truck back on, shifted to drive and was able to move from intersection without being hit.. the Colorado was taken to the dealership a few hours later and the error code had cleared already. Service advisor stated the car was safe to drive and there was no work to be done as their were no warning codes and the check engine light was not illuminated.

- Ladson, SC, USA