I have a 5.7 vortex engine that cranks and idles fine. When you try to accelerate the engine bogs out even all the way to the floor. If you let off, it goes.
Fuel Related issue from the sounds of it. While someone presses the gas pedal and it starts to bog, spray some starting fluid in the air filter. If the engine revs up, you know for certain it is fuel related. Most likely the fuel pump is going out. Fuel pump failure is quite common on these trucks. Of course change your fuel filter at the same time. You may also want to insure the fuel pressure regulator isn’t leaking. Normal fuel pressure should be between 60-66 psi. Use a fuel pressure gauge to check this. When you press the accelerator the pressure should increase. If it drops, the regulator is bad. If the pressure is below normal the fuel pump is shot.
If the check engine light is on, pull the codes and post them below in the comments.
Fuel Pump Replacement 1998 Chevy Silverado when the Engine Bogs
Warning! Unless directed otherwise, the ignition and start switch must be in the OFF or LOCK position, and all electrical loads must be OFF before servicing any electrical component. Disconnect the negative battery cable to prevent an electrical spark should a tool or equipment come in contact with an exposed electrical terminal. Failure to follow these precautions may result in personal injury and/or damage to the vehicle or its components.
- Remove the negative battery cable.
- Relieve the fuel system pressure. Loosen the fuel filter lines
- Raise the vehicle.
- Remove the fuel tank.
- Remove the fuel sender unit assembly by turning the cam lock counterclockwise using tool J 39765 . Or a hammer and straight edge(Screwdriver)
- Disconnect the fuel pump from the sender assembly.
– Pull the fuel pump up into the attaching hose while pulling outward from the bottom support. – Do Not damage the rubber insulator or the strainer.
- Inspect the fuel pump attaching hose for signs of deterioration.
- Check the rubber sound insulation at the bottom of the pump.
- Inspect the strainer.
Here is a replacement fuel pump. I have double checked to insure it will fit your vehicle.
- Install the fuel sender assembly into the fuel tank. Insert a new O-ring seal.
- Install the cam lock assembly. Turn the cam lock clockwise to lock it.
- Install the fuel tank.
- Add fuel removed from the tank.
- Check for fuel leaks.
- Turn the ignition ON for 2 seconds.
- Turn OFF the ignition for 10 seconds.
- Again, turn the ignition switch to the ON position.
- Check for fuel leaks.