I have an early year (Jan) '1994 E350 with a 7.5L. Many of the engine parts I have replaced on the engine are '93 parts (the '94 part's won't fit). The van has always run a bit rough and I decided to check the PCM. The van is running with a '94 remanufactured PCM 78-5889. Since it was replaced before I bought it, how do I know that the original PCM wasn't a 1993 78-5549, or 78-5292 model?

Any help is greatly appreciated!

 

Have you tried calling Ford and let them check with your VIN number?
you might try here by VIN:
Official Ford Parts Site | Buy Motorcraft & OEM Ford Parts Online | FordParts.com

NumberDummy here at this site might also be able to help you

 

Post the calibration number off the drivers door "B" pillar and I will try and post the FORD part number and the engineering number of the PCM.

Note that the numbers you listed are not Ford numbers, they are Cardone Industries numbers.

I would go to a salvage yard or ebay and get the right PCM by the number you get from the calibration number and not use after market rebuilt junk. You may have to replace the caps in the salvage yard or ebay PCM. But caps are only about $1.00 and you will know you have the right PCM.