1999 gmc sierra 1500 wont start

I drove threw a little water on hiway with other cars (no water appeared to get under hood) truck lost power didn't die right off, a few seconds later lost power , sputtered and died. try to start it and it started but only for a couple seconds never really a true start but a sputter. did this several times then got towed to safer area and let sit a while tried again and it did same sputter a couple times , now no sputter it just cranks over. changed fuel filter, plugs and wires (as they were all old but probably still ok), other than freak timing with a fuel pump or pressure regulator going out at the time I went threw the water what else could I test? it is getting no (zero) pressure on fuel pressure testing gauge and I think the initial sputtering while trying to start it was perhaps residual fuel in the line. also I am not hearing anything from fuel pump but not sure if I ever had heard anything before (with the dinging sound of key in ignition). also I checked fuel pump relay in fuse box and am getting a reading of 85 or so with ohm meter. any thing else possible before trying to change pump? 1999 gmc sierra slt 1500 5.3 2wd auto trans has about 165k on mileage.