1996 Ford Thunderbird OBDII Monitors Keep Resetting for no

Lets see if anyone can figure this out. I got a 1996 thunderbird 3.8L. About 2 years ago it passed emmissions no prob. This year I goto pass the INDIANA OBDII test and I fail all 4 Monitor tests (Cat, EGR, OXYG, Etc.)

They tell me to drive the car, drove it 150 miles and checked the monitors and they all say OK based on my code scanner. (No check engine lights came on car runs fine) and NO I did not clear codes to reset computer. I'm not that stupid. So I drive to station and again it fails all 4 monitors! I plug scanner in when leaving station and sure enough they reset all back to "INC"ONCLUSIVE.

I have tried this 4 times (state allows 4 tests) and all failed after driving 500 miles!

Had it scanned by shop that said nothing was wrong and they told me to drive it also!

Another buddy with a MAC 2500 Scan tool told me that the computer is probably bad. So I goto the junkyard and find another computer and grabbed the mass air meter also (to have a matched calibrated set).

Drove the car to work and checked it and all monitors said OK. So I drove home and checked it in the morning hopefully to call and ask for another test and ALL the monitors are reset again.

I am wits end with this car. I've been driving 2 months now with expired plates ( dont want too) because I just cant figure this one out.

Is it possible that the battery voltage it cutting out when off (bad ignition switch?) I've had a OBD scanner hooked up to the port and it never shuts off so I'm not sure if that 12V with ignition off comes from the computer.

Any help would be greatly appreciated!
Thanks,
Brad M