95 Jeep Grand Cherokee Laredo Sputtering

I am at my wits end. I have a 95 Jeep Grand Cherokee Laredo 6 cyl. About 2 months ago it started acting crazy. I can start it, drive it just fine for about 20-30 minutes. Then all of the sudden it will start bucking and sputtering when I press the accelerator, but it doesn't stall out (well. One time it did). Running the Air Conditioning seems to speed up the time it takes to start Sputtering. I have changed the Fuel Filter, Fuel Pump, TPS, Oil Pressure Sensor, Temp. Sensor, Crank Position Sensor (about a year ago), and standard tune-up stuff like Rotor Button, Dist. Cap, Spark Plugs. Nothing seems to fix it, and it does not throw any Codes to the computer. Anybody else had this problem, or got any guesses as to a solution?

Thank You.