Strange Missfire ???

Trying to repair a 94 with a 5.8 and started with a missfire that felt like secondary ignition so with 200k on it I have replaced everything from the Dist, coil, wires , plugs, etc.. only to still have this crazy miss or cutting out scenario. The miss feel like more than a single cylinder and will cause the van to buck or jerk when under a load such as going uphill. When crusing with your foot light on the accelarator it does noit miss as bad but still does it.
I'm wondering if it is dropping an injector or two and how common injector failure is on these. I don't seem to be loosing injector signal but when it hiccups it almost like you cut the key off for a split second & turned it back on. Yoiu can also see a voltage surge or drop on the gauge when this happens. I hope someone can help me save what little hair I have left because this thing is driving me nuts - thanks for any ideas !