1997 Chevy z71 5.7 vortec 4x4. Fuel problem.

It is sounding like leaky injectors, spider lines, and fuel regulator. Pressure dropping to 0 within 3 minutes is a good sign, It should only drop no more than 5 lbs in 3 minutes. Fuel pressure should be 56 to 63 lbs. I would do a dead head test on the fuel pump itself to verify that it is putting out 64 to 68 lbs.

I second injector assemly.

i was having the same issue in my 97 k1500 i got this truck super cheap because the previous owner got sick of messing with this same issue. i changed about 4 or 5 fuel pumps with in 5 months and then decided to look further into it. i had power at the relay and pump but it would keep dropping out and bogging down. after a ton of digging and research i found that my fuse box under the hood (where the fuel pump relay is) was not making a great connection so when hitting bumps slowing down and trying to accelerate the pump was actually turning on and off causing it to to bog down. i ended up running my own power wire to the fuel pump and put a relay in the power line, only down side of doing it this way is that the pump is on as soon as i turn the key on. the pump normally turns on and then off after somewhere around 10 seconds and then we then when started it stays on. So if you want to listen to music while not driving your pump is going to run. But my truck has been running great since, about 10 months now and i drive my truck about 100 miles a day.