My wife and I primarily use the front fuel tank on our truck.  It's a
5.8L with enough miles.  I started applying some simple rules to eliminate
the problems after it dawned on me that I might have a possible fuel
pressure problem.  It though it would be the fuel pressure regulator, but
wanted to try a few things out.  Swapped gas caps out and that didn't do
anything, but I did start using the back tank and the problem went away.
Sort of.  What happens is that when you put your foot down and are drawing
from the front tank, the engine stumbles, but will run fine as long as you
take it easy on the gas.  The other thing is that I'm thinking the valve in
the pump is letting fuel pumped from the rear tank into the front tank.
Haven't run it dry yet to confirm that suspicion, though.  My wife isn't too
fond of using up that gas, as she keeps her foot in it too often.
   Since I'm cheap, and broke (as always, it seems) I was wondering how
much I could trust a pump (fuel delivery module, in Ford parlance) from a
wrecking yard.  I haven't heard of much in the way of issues with these, but
can't afford a new $140 aftermarket pump right now.
   Any suggestions about taking the front tank out and swapping the pump
out?