Fuel pump won't come on

It sounds like the pump has failed which is common here is a guide to help walk you through the steps with instructions in the diagrams below to help you with your car.

https://www.2carpros.com/articles/how-to-replace-an-electric-fuel-pump

If the pump comes on and supplies pressure when you apply voltage then we most likely have a voltage issue. So we need to make sure the pump is not just coming on with no pressure.

However, I am including the wiring diagram below for this issue as well.

If you check the voltage at the relay you should have 12 volts on the red wire which is the voltage supply and then the PCM grounds that circuit on the Light Blue Orange wire which will close the relay. Then if the inertia switch is closed it will supply voltage to the pump. So we could have a relay or switch issue as well.

https://www.2carpros.com/articles/how-to-check-wiring

Check out the diagrams (Below). Please let us know what you find.

Usually, if you have a low voltage, it means there is a high resistance somewhere in the circuit.
'Somewhere' is the word here. It's impossible to tell which part is defective until you check all the components of the circuit for high resistance (wires, relay, fuse, etc).
Keep in mind that a component that 'looks' good is not necessarily working right.
DON'T check components by doing a continuity test; it will only tell you if there's current going thru the component but not if there's ENOUGH current going thru it.
You need to find what the normal resistance is for each component, and then do an Ohm test and compare what you have with what it should be.

I'll be honest, troubleshooting an electrical problem can be a pain in the butt.
I would not do this until I've rulled out any other possiblities.

If your voltage reading at the pump is normal when you turn your key to 'start', low voltage is probably not the problem.

Hi blademan7, Welcome to 2carpros and TY for the donation.

Check and test fuse no.4 30amp and fuse no.22 20amp in the engine compartment fuse/relay box, the PCM power relay in the center of left fender apron and the inertia switch at below right side of I/P below glove box

The truck did start once since this started, ran rough engine light flashing. Now nothing.

What is it doing now? Is it cranking over and will not start or just won't crank at all /nothing

Is it the check engine light that's flashihg?

Power the fuel pump direct from the battery and tell me what happened-this is beginning to be a nightmare. If the fuel pump comes on-have the computer tested-

Like you said the inertia switch, fuel pump relay, PCM power relay and the fuses been checked and tested good-last place will be the computer controlled of the relays one goes still has to be replaced

Have you performed any diagnosis on the vehicle yet? Checked fuses/relays and/or inspected the wiring to the fuel pump? Below is a wiring diagram for the fuel pump system on your vehicle. I've also attached a diagram of the under-hood fuse box showing the location of the fuel pump relay and fuel pump fuse(fuse 22). Let me know what you find.

Sounds like the PCM control of the relay has gone bad. The power for the fuel pump comes originally from fuse no. 22 20amp, when the computer energizes the relay it powers up the pump thru the inertia switch this is how it works