Silverado's have a rubber hose in a section of the fuel line near the tranny. With time, heat, and high fuel demand the hose will constrict (partial collapse) because the Silverado uses vacuum from the fuel rail to suck fuel instead of a lift pump to pump fuel through the filter and lines.
The truck CPU thinks the fuel filter is clogged or the injectors are clogged, or ??? but the result is you have reduced power. If you stop and let it sit a few minutes the hose cools down and resumes the correct diameter. The truck runs fine until you get into another hot, high fuel demand situation. Like climbing a hill on a hot day.
There is a Tech bulletin on fixing the hose or you can have a aftermarket lift pump installed or both.