97 silverado won't start.

Truck was running perfectly fine. Got up to go to work Monday and it wouldn't start. 131,000 miles

I've done the following. Thinking it was long overdue for tune up.

Plugs, wires, cap rotor. Still won't start.

Would fire momentarily with starting fluid. Wasn't sure fuel pump was working and convinced it isn't getting gas. I changed pump and fuel filter. Still won't start Again it will start momentarily with gas or starting fluid dumped down it. I know nothing about fuel injection. But i'm starting to think that way. What do i look at next?
How do you check your fuel injection system?
Any advice would be greatly appreciated.

There is a pressure valve that you can check to see if fuel is getting to the injectors and see if the pump if pressurizing. It is located over the rear of the engine closer to the drivers side. It is supposed to have a plastic cover over it but those get lost easily. It resembles the top of the valve stems on your tires. If you depress the center button after trying to start the vehicle, gas should spurt out. That's not to say you have enough pressure but at least you know gas is there.