Checking fuel pump pressure?

[_Spanish_]

Hey everyone, was wondering how I would go about checking my fuel pump pressure. Second time my gf runs out of gas on my 04 Yukon SLT and now if I park downhill with about 1/2 tank it won't start till I put another 20L but so far no issues if I park uphill,even with less then 1/2 tank.

 

[01ssreda4]

Take the schrader valve out of the rail and hook a fuel pressure checker to the rail. Easy as pie.