Does the Chilton'* have a wiring diagram? Could all of those parts receive their voltage from a common source? I had a vehicle a few years back that wouldn't start that caused some real diagnostic headaches for a while, and it threw several codes that seemed to be unrelated. I found that one sensor had shorted, removing the voltage from the others. In that case, it was the fuel tank pressure sensor, which you don't have, but you may want to check the supply voltages. If low, when you unplug the bad sensor, the voltage to the others should come back up to normal.
Black 2000 SSEi, Silverstar Headlights, Angel Eyes fogs, 3rd brake light overlay, hi-flo cat, drilled 180 degree thermostat, Intense FWI, PCM, shift kit, and 3.4 Pulley. Solid front mount.