1996 Ford F-150 OBD2 monitors reset at key off

I just bought a 96 f150. I need to get it emissions tested, but am having a problem. Every time I turn the key off for more than about a minute, the readiness flags reset. I have driven it a few times with my scan tool plugged in. If I drive it long enough, eventually most of the monitors will come on line, with the exception of catalyst and EGR monitors, but as soon as I shut it down it starts all over with every readiness flag but the misfire and fuel system flags not ready to test. The readiness flags that are reseting are the O2, O2 heater, secondary air, component monitor, EGR and catalyst. No driveablilty issues though. Thanks.