hello, new guy here with some Q's

Ok first off, hello all, im glad to be a member here finally!

I have a 1997 Chevy Tahoe 4D with a 5.7.
The fuel pump recently went out so i changed it and it ran fine for 5 days.

I was on my way home from work and it just quit, mid-transit. I checked to see if i was getting power at the relay station, i am. I then proceded to remove the tank and get ready to conquer another fuel pump change. (I was thinking i bought a bad pump)
So i dropped the tank and pulled the pump, exchanged it for a different one, checked the fuel pump connection to see if i was getting power there. i am, and the relay seems to be working fine. (I checked it with a Volt meter, i am getting around 7v on one hot, and 11.6 then down to about 2 when the relay engages.)
My pump still wont kick in. any ideas?

BTW, ive tried 3 different new fuel pumps to no avail.

Any ideas are appreciated.

Correct me if I'm wrong, but doesn't the FP run only when fuel is needed (demand pump)?

Could it be a clogged/pinched line or clogged fuel filter causing the pump to think the lines are full and it doesn't need to pump anymore?

No, it's on all the time. Fuel is pumped at a specified flow and pressure to the pressure regulator. Excess fuel is returned to the tank through the fuel return line.