[ChevyTech]

The only unusual thing I notice with your photos, other then the rubber injector grommets on the wire connectors are missing, is they are upside down.

Your truck has a “Port EGR Valve/ System” and you may want to make note of this for future reference. If you ever want to buy an EGR valve they will most likely try to sell you the wrong type.

The return line is smaller diameter and is to the passenger side of the supply line.

Test the fuel pressure. If the pressure is good with the engine running then the return line should be open.

The rubber hose and clamps on the fuel supply line between the tank and the fuel filter are NOT factory.

Lifting the bed is the method I prefer, rather than dropping the tank.