So you 2nd gen guys know... you truck has spare relays already in it. If you ever get to the point where the FASS relay quits, just pull your Horn or fuel heater relay from your under hood fuse box and plug in. (You can also test the FASS relay by swapping it and honking the horn) Will get you to a parts store or home.
I wouldn't worry about your VP... like mentioned it takes neglect of fuel pressure over some time to really do damage... mine has dropped when i pushed my luck with my fuel light in my truck. AND im still going just fine. Did my VP last year as well... . (Dang electronics... ..... moot point)
Hate to say it, but its hard to test for a problem that isnt happening... my suggestion is to recheck all your connections at the BATT, relay, pump and stock engine harness. If the issue happens again, make note of fuel level, engine warm, cold, driving, coming to a stop, turning a corner... . etc... .