Missing under load

Well, I got the engine in and running. It runs good at idle and crusing at about 50. If I accelerate hard, it has a dead miss. It also misses with the throttle partially open in park. I've pulled the electrical connector off of the injectors one at a time (easier than pulling the plug wires) while a friend held the throttle open. It definitely made a difference on each cylinder when I pulled those. With all of them back on, it still sounds like it is missing to me. Occasionally under hard acceleration, all cylinders hit and this thing romps! I can't figure this one out. Any suggestions?

Tom