I have the same issue. Mine is an 05 GMC sierra quad cab 5.3 It presently has 315,000. Last summer the air would blow heat. I would turn the truck off and restart either going down the road or at red light and would work fine. Then a few weeks later under heavy acceleration the whole thing shuts down and reduced engine power. I recognized if I turn the truck off let sit for a few the service engine light comes on and if I just drive it normal it will eventually go off as well. I have now started dealing with lifter noise and it wants to cut out particularly going up mild hills. Is this all because of the TP sensor?