John Moonen

I have a 2016 Silverado 1500 with the Northland package. Truck started acting up last week. Was driving on highway with cruise control set, trucks grade braking come on, RPMs maxed out at 6000 and transmission dropped a few gears, very roughly. I was on level road. Now ever since the cruise control does not work, grade brake kicks on at any speed and there is no power when i step on the gas. If I turn grade braking off it will drive somewhat normal but still no power during acceleration.
Brought to dealership and they say compression issue because no power.
local shop thinks its a sensor on the brake pedal.
Anyone ever hear of this happening?