Hey everyone,

I've been going over the wiring on my truck because of an intermittent stalling issue and weak fuel pump pressure. I happened to notice two wires that aren't properly connected. The green wire is completely severed, and I can't tell were this white wire with the connector goes - thinking ground, but I could not see a potential attachment point. This picture was taken laying on my back looking up at the rear bumper area. The wire loom goes up into the box and is inaccessible. I think it works around the rear fender and then comes out on the frame, joining the wiring from the front fuel tank and others but not entirely certain given its inaccessibility.

 

Severed wires will not cause low fuel pump pressure, corroded wiring and connections can.. The pump will not operate at all if one of its conductors is severed.. The white wire does appear to have a lug on it that may have been attached for a ground before it corroded away. I see two ends for the green wire.

You mentioned those wires are near the rear bumper so that makes me think they are for rear lighting or someone used them for trailor lighting.
You need to verify a 12v feed and good ground at the fuel pump itself first before changing the pump.