1990 Jeep Wagoneer engine not accelerating, cuts out on hig

i have a 1990 Jeep Grand Wagoneer with 167,000 miles on it,it has the 5.9 liter 360 V-8 and it is carburated and i just started having a problem with it. when i am accelerating, the engine stalls and runs very rough, it acts like it is not getting enough fuel, but i have replaced the fuel filter and pump. the other probem i have is when i do get it to highway speed (55-60 mph), it cuts out and starts to dramaticaly lose power, so much to where i have to pull over and limp my way back home. i have replaced the following items on the car; fuel pump, fuel filter, all news plugs and wires, as well as ignition coil and rotor cap, new alternator, and new starter. i just had the timing checked and adjusted and the carb tuned up. i thought i might have been the catylitic converter, but the previous owner cut it out. could it be the transmission going out? any sugestions would be greatly appreciated as i am a college student and i am trying to fix it on my own to save money. thanks