This is 2002 Ford Ranger - not Ranchero. This truck has butchered up/patched up fuel lines which I need to replace. As I see it, Ford ran two nylon fuel lines from the tank to the fuel filter under the cab and then one nylon fuel line on to the engine compartment. Playing with a new fuel filter, I believe the two fuel lines from the tank connect to empty space on the inlet side of the fuel filter. A centered port on the inlet side of the filter is 5/16" diameter. The other port, offset to the side, is 3/8" diameter. I assume here that the 5/16" port is pressurized fuel from the pump and the 3/8" port is a return to the tank. The two nylon lines from the tank to the filter appear to be the same size although clearly the (missing) quick connectors would have been different sized. My real question is why did Ford do this? Why run a return line all the way to the fuel filter? Why a return line at all except to always have flow through the pump to prevent over heating? Why nylon fuel line? I see it as difficult to splice without heating - ugh!