P0340 I take it? You'll most often get this code when using any camshaft position sensor other than one installed at the factory. The original OE source went away a long time ago so even a new Mopar sensor is not the same. I don't have a perfect solution but I would bet that the Echlin part from Napa is pretty close to OE
If you're getting P0016, the OPDA is not properly clocked and the corolation between the camshaft and crankshaft sensors is beyond what the PCM can compensate for. If this is the case you'll need to use a DRBIII scanner to synch the two sensors or remove the OPDA and set the engine to TDC.
As for PCM failures: With the auto you'll often see odd transmission temp readings, like 1800-3000 degrees. Another is a harsh 1-2 shift on cold start. This 2nd issue I would suspect is a memory failure due to a bad capacitor, where the PCM is having to relearn the shift points every day.
Another common sign is codes for all 4 O2 heater circuits.
I've only seen one instance where P0340 and crank no start turned out to be the PCM.