93 f150 4x4 cuts off under hard acceleration

Hello i have a 1993 f150 4x4 with a fuel injected 5.0. The truck will run fine and idles smooth. When i get on the highway or in the mud the truck runs good until i floor it. Tryin to figure why it only cuts out under hard acceleration. Got new plugs, wires, distributor cap and fuel pressure regulator. Yes check engine light is own but its allways on lol I usually dont trust em anyways