Cruise Control problems of the 2016 Chevrolet Colorado

Numerous times while driving, and going downhill the truck shifts to a much lower gear causing the rpm's to go up to 5500 and does not shift out. Twice I had the cruise control on and was on the highway (speed of 75) going down a hill and it shifted to a much lower gear. It has done this on other roads going down hill as well. In addition, numerous times when merging with traffic on a highway, I will try to tap the accelerator to safely merge with traffic and the truck has gotten "stuck" in a lower gear and would not shift out and I thought I was going to rear end a car so I had to ride my break to make sure it would not continue to accelerate into the back of a car. In addition to that, often when trying to accelerate out of a corner or after an off ramp, the truck will not accelerate at the same rate as the other vehicles around me. It will slowly accelerate as the vehicles around me pull away. In addition to that, when I am on the highway and I need to accelerate quickly to safely pass traffic, I have to push the pedal to the floor to ensure that the truck will actually accelerate. The dealer just tells me that the software is up to date and they could find no record of similar issues.

Engine revs high coming to a stop. Required both feet pressed hard on the bakes to emergency stop. Speed control quits working then service-stability control comes on, car starts to handle ackwardly, pulls to left then. Cut engine off and it resets, but the cruise control stops working and then that service stability control comes back on. If I don't put on the cruise control, I don't get that stability control message so far. Braking problem happens when comes to a stop. Cruise control happens at highway speeds but sometimes going 45 mph.