Low fuel pressure

[DDlighttruck]

Fault code 482 Fuel Pressure Low

Fired right up this morning. Ran 10 minutes (drove up to the front of the lot), turned it off and had breakfast. Came out cranked for 10 seconds, no fire. Turned key off then on, fired second crank.

Drove 45 minutes up the road. Check engine light came on. Then it quit completely, managed to get it parked. Popped the hood, fuel water seperator was empty, turned the key on watched the fuel water seperator fill up with fuel, it restarted, I drove 50 feet and it quit again, fuel water seperator is empty again.

That's the fault code that came up and I can't see where to read fuel rail pressure using Powerspec. Mobile tech is on his way now but I'd like to be able to diagnose this stuff myself.