2008 Ford Escape Mechanical Issue

I own a 2008 Ford Escape V6 and when I hover steadily over a speed (usually 60/80km) or steadily hold speed going uphill my car gives me a little kick back/jolt feeling. I've brought it in to numerous shops and no one can figure out what is wrong. Has anyone had this problem before? I've chanced a solenoid valve, flushed the transmission, replaces the fuel filter and fixed a wire in my ignition and nothing has helped.