2008 Chevrolet Silverado 1500 stumbles in cruise control

2008 Silverado 5.3 Engine.
While driving with Cruise Control on, it stumbles, skips or something going up a medium hill. It will downshift two times and the RMP jumps to nearly 4000 RMP. Gas mileage has drooped. But sometimes it runs better than other times.
Thanks

Is the check engine light on?

How many miles on the engine?

How’s the transmission fluid?

Transmission fluid is good.
No engine light on. 260,000 mile on truck.
I have changed >
fuel pump
plugs
and a bunch of sensors

Which sensors did you change?
If you don’t mind me askin…

all oxygen sensors. fuel pressure sensor. crankshaft, temp sensor.
thanks