Rpms bouncing when accelerating 98 4.6 4x4 single cab f 150

What is your question?

When I accelerate hard my truck bogs down and the rpms start bouncing, the truck just kind of skips. Have replaced plugs, wires, coil packs, fuel filter, speed sensor, trans harness, air filter, oil, egr valve, and tps. I'm sure I'm leaving some parts out but it's getting expensive playing the guessing game. Need some expert opinion.

What makes this problem better or worse?

When I accelerate hard it occurs, when I let off it stops.

How long has your 1998 Ford F-150 had this problem?

Since I've owned the truck