Jet driver and SKOM...
2001 Chevy truck and a 03 Hoe...
My truck had a fuel pump start to go bad and here is the following way I diagnosed it...
Before testing it with the fuel guage... I was able to let the truck sit and everytime I tried to start it after sitting it was hard to start.
If I ran it and shut it off it would start right back up...
If I would turn the key to on (not to start) wait a couple of seconds, turn the key off and repeat. Then try starting the vehicle it should run fine.
What this proceedure does is builds the pressure in the lines back up...
If this works the way I wrote it I can almost guarantee you your pump is on its way out..
If that is the case.. When you hook the guage up to the fuel rail, running you will see right around 60 psi.. Shut the vehicle off and watch the guage. If the guage slowly falls to zero your fuel pump is faulty..