Truck Repair: 94 gmc truck 305 no take off power, throttle body injection, tail pipes

Question
Ok here goes 1994 gmc 305 runs great, just when you step on gas it just bogs down for a couple of seconds and then takes off. This is what I've done to her so far o2,mapp,tps,plugs,wires dis. cap,rotor button,computer,checked timming & timming chain.. Checked from tip of tail pipes to ex manif. for block or stopped up.. Ever thing I do the truck does the same thing. My truck has alot of miles on in but it's one owner and she been taken very good care of....I would be very greatful for any help you may give.. Tkanks    John

Answer
Hi John,
First thing is to check the fuel pressure.
You could have a dirty filter, a bad pressure regulator, or what i suspect, a split or hole in the rubber hose inside the tank, where the pump connects to the line coming out of the tank unit.
A pressure tester will tell if the pressure is not up to spec, and it needs the correct pressure.
If it is throttle body injection,
It needs to maintain 13 PSI at the throttle body, at all times.
Other types of injection is higher.

Van