How can I fix my 1994 chevy s10 pickup?

It cranks and runs but the engine acts like it isnt getting enough fuel. Once it gets warmed up it spits and sputters like it isnt getting enough fuel when I shift gears. It is a 2.2L four banger motor. I rebuilt the motor. Including replacing the crank, the oil pump, one piston rod, all the seals, the plugs, plug wires, fuel pump, fuel filter, and now the EGR valvue. I also ran it for a while to see if it just had trash in the system. I bleed all the air out of the fuel injection system, and it still does it. If you have any clues to what else could be the problem please inform me. Before I rebuilt the motor it ran fine without this problem.