So i got my truck from someone and it had been sitting awhile noticed front tank didnt work.....engine cut off right away so ive been using rear tank with no issues. The other day i noticed gas leaking from front tank cap, took cap off and gas poured out. Now it runs on front tank although gas gauge reads empty with tank full. There is some noise assuming from pump when on front tank. I did run some multi system cleaner through rear tank in hopes to resolve a hesitation issue. I went through the whole tank and a half when leak started. I read something about a selector valve on frame rail but my truck dont seem to have that all i see is pretty much a plastic looking y splitter for main and return lines. So how does fuel not feed into tank not being used and what do i need to do to remedy this issue truck has the 4.9

 

There was an old factory recall that installed check valves on each of the fuel pumps in the tanks. You don't have the selector valve...the switch in the dash turns on the fuel pump that is selected.