Studder above 3,000 RPM when warm

i have an '88 5.0 GT. When I get on it, it begins to studder and cuts out very badly above 3,000 RPM. It only does this when its warm and under load. It always revs freely to the redline. Below 3000 RPM, it runs like it should, and it runs great when it is cold. Only after the car has been run for about 10 minutes. The car begins to blow smoke while cutting out. The problem happens everytime I run the car above 3000 when warm. I have changed the cap, rotor, plugs, pulg wires, ignition module, and ran fuel injector cleaner. I think the problem is an 02 sensor, the temperature sensor that is on my intake manifold, or a bad distributor. does anyone have any ideas?

re: studder

it doesn't put out any codes according to my local shop, but they said something about taking it to a ford dealership to have all of the codes checked. I dont understand why he could check some codes but not all of them. The mods are just bolt ons, bbk shorty headers, mac off road h-pipe, turndown mufflers, march pulleys, FMX trans, stock timing, and i dont know what the fuel pressure PSI is, but would that be effected only after the car warms up? no other weird sounds other than when it cuts out. sounds almost like a miss.