What would cause my truck to stall out at 75mph and above?

I have a 93 Silverado K1500 5.7l Z71. When I drive down the expressway if I drive 75mph or above the truck stalls out for a second like I hit a governor or fuel cut off, and then will catch itself and keep doing it. If I drive at say 73mph it will not do it. When it does stall out I can flutter the gas pedal and nothing happens. I have recently done quite a bit of maintenance on the truck. I replaced the fuel pump, fuel sending unit, fuel filter, plugs, wires, cap, rotor, MAP sensor, TPS sensor, coolant temp senor, injectors, fuel pressure regulator alternator, and throttle body gasket. All were changed before this problem started and after a couple of weeks of driving the problem started and that's when I changed the TPS. Any ideas of what I can look at next. I believe right now I need a new EGR valve and u joints, but I don't see either of these being my problem now.