I have read many complaints about this same issue. It first started with my car slowing down, didn't matter how hard you press the gas it will not move. Then after letting it sit of a minute/cool down, it will ride for a few miles then completely stop with the engine still running. I notice a hot smell coming from under the hood.

The traction control light and stabilitrack state that it needs service. When I drive it the brakes stop the car on its own. I took the car to GMC and it cost me $1700 for them to fix brake pressure module, brake electric control panel, I replaced hub bearings and the problem is still there. Since those things were replaced, I can drive a little longer without the hub bearings. I took my car to GMC 3 times. And my airbag light is on and they said that need to be replaced, How when it was never used.