Hey everyone I’m a new member so if this topic is in the wrong area please just let me know. I have a 2007.5 GMC Sierra slt with a 5.3, it’s an extended cab 4wd as well. The issue I’m having is that I have no fuel pressure at the rail, I have disconnected the fuel line at the pump and it is pumping but I haven’t tested the psi. This is the 2nd fuel pump I’ve put in the truck and I also replaced the fuel flow controller that’s on top of the spare tire. I can blow air through the line and air gets to the other side so there is not a full blockage somewhere. The truck was running but would lose pressure and Rpms would drop for less than a second once every few minutes but now the truck will not start at all. The truck has had the issue now for 6-7 months and has been not running for about the last month. Any help at all would be very much appreciated as I have no idea what else to do.