My fuel pump went out on me a couple weeks ago and at the start of the replacement i had my sanity intact. So i tried to remove the gas tank. I got 6/8 bolts out before i rounded one off. I knew a few other people here had done fuel pump access panels and in my frustration thats what i did.
Tools needed: Phillips screw driver, grinder with a cut-off wheel, maybe a knife (i used one).
WARNING: FUEL IS EXTREMELY FLAMMABLE!! LOTS OF CAUTION NEEDS TO BE USED WHEN DOING THIS AND A FIRE EXTINGUISHER NEEDS TO BE WITHIN A ARMS REACH.
First lower your tailgate and unscrew the trim piece holding down the carpet.
After that is removed pull your carpet back as far as you can. Locate the two panels for the body mount bolts.
the fuel pump sits about 6-8 inches back from these access panels. So on your floor measure about 4-6 inches back to make your first cut. The fuel pump is directly in the center of the bed. so measure out about 10 inches in width and make your cuts. If you did it right you should see something like this once you remove the cutout of the floor
I havent got to a junkyard to cut me out a replacement panel yet that will cover the hole. Another way to cover it up would be to get 4 1"x2" pieces of sheet metal and use self tapping screws to secure the panel in place.
Fuel pump removal tips: the retainer ring holding the fuel pump in can be a pita to remove. after tapping it for about 10 minutes trying to get it to slide i used a chisel to bend the ring and ply it up. As long as you go slow and dont break the ring you can beat it back straight with a hammer.
I will update this thread once i build the replacement panel.