1997 Plymouth Voyager P0300 code engine running rough

Engine Performance problem
1997 Plymouth Voyager 6 cyl Front Wheel Drive Automatic

My car shut down without warning on several occasions and would restart almost immediately when I coasted to a stop and placed it in park. I have replaced the crankshaft position sensor, the camshaft position sensor, the ASD relay, And the fuel pump relay. Runs now, but still shows P0300, P0301, P0305 codes. I took her into a Chrysler/Dodge dealership for analysis only. They told me that they could not pinpoint the problem without keeping the car for many hours. Initial thoughts that there is likely a wiring problem and they would need to inspect all wiring, but they could not rule out other causes such as a Powertrain Contol Module (PCM) going bad. The spark plugs, wires, and distributor cap/rotor have been replaced approx. 2 years ago.

How likely is it for the PCM to act like this? I was always under the impression that if the computer control modules went bad nothing would work. Am I wrong? Could it be the PCM (or other engine control module) not functioning properly? Perhaps a bad coil?
Also, I had to replace the Crankshaft Position Sensor (CPS) twice. The car shut down again a couple of weeks after I had replaced the CPS the first time. I replaced the CPS and the car started righy up, but still shows codes. I have previously asked similar questions about this same issue here without much help. I am asking for continued help.