I suspect the fuel regulator.

Hello and thank you for this wonderful service. I have a 2000 ford expedition 5.4L. Every time I make a sharp turn, u turn, go over hard terrain and hills, my engine bogs down for a quick second, and then continues. And sometimes, I could feel a loss of power. They replaced the fuel pump 2x's under warranty and still the same problem. Could it be the fuel regulator? Thanks. Jose