Please help
1995 k1500 silverado 5.7L
The issue is the truck has 380,000 miles first
The real issue is as you are driving normal or high speed
Day or night , hot or cold engine the truck feels like something is slowing me down. If I stop and turn off the engin and restart it , take back off and get up to speed ( 30 to 80 ) the truck might bog or may not .?
Some times it happens more in cold mode
Others never happens in cold mode only in normal heat range
New tps, iac, base gasket,, distributor , cap, button, wires, plugs,fuel pump
(Rear end( was different reason ) , transmission overhaul,
No cat installed , new thermostat, radiator ,
(All of these repairs was not due to the problems I'm having now except the
Base gasket, tps,iac,)

 

Correction
Slowing me down is = loosing power til I either stop by pulling over or it quits after a sec and resumes the speed

 

Sounds like a fuel problem.

Fuel pressure ok?

Fuel filter?

Tank vent?

(Things I would check)

Good luck! Let us know what fixes it!