I have a 1998 chevrolet K1500 5.7 L vortec mpi reg cab 4wd 120,000 miles.

I have 60 fuel pressure with key on and 50 fuel pressure when truck is running at the
port at the top of motor behind the spider injection. I get 1 pint of fuel in 7 seconds
using stop watch on my smart phone. I was able to drive my truck around my lot up
and down hills and back up into my garage while someone sat under the hood spraying
starting fluid into throttle body. I put 3 different 1/2 bottles fuel injection cleaner into a
little more than 1/4 of  a tank of gas. I sprayed crc, gumout,and valvoline throttle body
cleaner into the throttle body. the truck will start once in a while on its own now, but
only runs 4 a few seconds. most of the time it cranks strong, starts, and stalls
immediately. can someone tell me how to diagnose the problem or tell me how to fix
it?