Ok guys i have a 96 gmc k1500 5.7
Motor is a 99 out of a tahoe
Tranny is rebuilt
Tps sensor is new
Coil is new
Complete tuneup
New mpfi spider
New fuel filter
New fuel pump
Old fuel pump 52psi at idle
New fuel pump 52psi and idle
Camshaft retard is within specs
Heres the deal starts perfect idles perfect no codes.
Slowly give it gas everything is perfect let off gas its perfect
Hit the gas pedal hard and misfires randomly on random
Cylinders! Sometimes #5 is the worst sometimes
# 2 is the worst sometimes #7 is the worst but all will
Show a misfire or 2 during hard rev but not enough to throw
A code. Take it for a spin cant get up to speed hardly.

 

Have you changed the fuel filter? Driver's side along the frame. My 90 did exactly that but no codes. Runs great now.