Sorry to hear the problem. We have a 2000 Rexhall with the F53 chassis and our rig was doing the exact same thing. I had anticipated dropping the tank but the way the coach builder constructed our motorhome, they somewhat boxed in the bolts so I couldn't remove the tank hangers. Given that, I lifted the water tank and cut a hole in the bottom of the coach and swapped out the pump through that hole. It's worked fantastic ever since.
PS...yes, I replaced the fuel filter and swapped relays and all the other tips. A new pump fixed it right up. Good luck
