I have a 2015 F150, 2.7L V6 Ecoboost. I'll be driving with the cruise control set to 80, A/C blasting, and the outdoor temp around 90-95F. At about the halfway point up a moderate hill on the highway, the wrench light comes on (maintenance required). The truck immediately loses power. It will attempt to maintain the cruise setting but downshifts 2-3 gears for help. I usually turn off the cruise control at this point and continue driving with the pedal. During the rest of my commute, the hills are much less steep however, to maintain speed up any incline, I feel I have to "floor it" and again, the transmission has to down shift 2-3 gears. I'm thinking that the turbo disengages due to the demand of power required for the speed and because the A/C is on high. The next time I have to drive, after starting the truck, the wrench light isn't on and I don't have any problems.

 

Sounds like you gotta check the codes.