Truck jerking

My 91 f150 jerks and serges when I get over 2000 rpm.I have performed the following new ignition switch ,new coil, new wires and plugs,new fuel filter, new o2 sensor,transmision fluid and filter change and oil change.HELP!!!

What about the distributor cap and rotor? The ignition module on Fords is often suspect when things get erratic in the spark department.
I would wonder if it was running out of fuel. I would put a fuel pressure gauge on it, tape the gauge to the side mirror, drive it, and watch for fuel pressure fall off during exceleration. You?