Y Does fuel pump keep breaking?

what's up everybody,
I recently just work on my truck (91'b2600) and b4 it was running well i was boggin out when ever i stomped on the accelerator pedal, so i checked the ECM , MAS, o2 sensor, the crank angle sensor, sensor tat screws in2 the intake manifold, check my compression, timing, idle adjustment/ gas&air mixture, the plugs, wires, rotar, cap, fuel filter,fuel injecters, electrial, among other things the problem kept leading me back toward the some thing that had something 2 do with fuel......
I checked the fuel pressure without a gauge just using my eyes it seemed 2 flow fine but when i checked the pressure with a gauge it was about 1/3 of what it should be.
I hooked up the fuel pump to 2 wires on to an 18volt DeWalt. While the battery was connected it would drive normal, but as soon as i disconnected the DeWalt drill battery it wpuld die.
I remove the fuel pump & get 1 from salvage yard. I install the newer 1. Truck runs fine. I drive truck for about a month.
I try 2 start Truck 2day & it wont start. I remove Fuel pump. I test it, but it needs a slight tap to get it going it looks 2 be working. I install back in2 Truck put gas. Truck wont start.

fuel pump has died or clogged
or
im not getting the correct amount of Voltage (once again)

my Questions:
Does any 1 have any idea Y my fuel pump keeps breaking down ?
Has this same problem (or a similer prob.) happened to any 1 else ?
What did i 4get 2 check or replace ?
Could it be a short?

I am now gonna remove it after checking the electrical connections & filter. if i dont get it running i think i'll just buy a fuel pump brand new
Thank U for reading. I shall keep u posted

Rust in the tank?

Clogging the fuel intake sock?

Cusser,
It was caked in rust the 1st few times i've changed the fuel pump, but i cleaned it out pretty goo (not perfect i said good)
and whats the fuel intake sock ? is that the flat filter chingadera that attaches 2 the fuel pump? & if so do u know where i could buy 1?
thanks i'll check it out while im dirty

does your truck start spuddering really bad when you give it any throttle?

New fuel sock on the right, from Dan Atkins (sponsor here, " target="_blank), as the stock one wouldn't stay on any longer, and was resting at the bottom of my tank.

New fuel sock on new B2200 sending unit from Dan Atkins


Photo of inside of my fuel tank, using special inspection camera, a gift from daughter. Photo shows no rust or debris!!! Guess that's how I survived for many years without an attached fuel sock.

There are many different styles. The one Cusser shows is for the carbureted engine. Most EFI socks look similar to these.
Any parts house should be able to supply one.

(2).jpg