hey everyone. im new to the site and this site seems very knowledgable. i just bought a 88 mighty max with a 2.0l carb'd engine. im having acceleration problems. when i drove it home it would hesitate anytime i pushed the gas unless i very easily pushed the throttle. so i checked the timing and it was off so i set the timing back to manufactures specs. i also replaced the wires, plugs dist cap and rotor button. now since i have done all that when i go to take off it accelerates fine in 1st gear but once i hit second it starts to stumble like its starving for fuel. so i have to ease into the throttle again. i have figured out that i can feather the gas between 1/2 and 3/4 throttle and i can feel it picking up slowly then it just takes off like its suppose to. i hope this is not too confusing but i want to figure out whats wrong with it so i can drive it. i dont know anything about these trucks since iv been a chevy man my whole life so hopefully some of you guys can help me.

one more thing that may help, the previous owner unhooked the manual fuel pump and hooked up a universal electric fuel pump.

1. could this have anything to do with the problem im having above?
2. how hard is it to replace the manual fuel pump and would it be worth it?

thanks in advance for any help!!!