[shorod]

I had seen that before on the OBD Fords, but not on the OBD-II vehicles such as your Sport Trac. On the OBD systems, one of the KOER tests is to run the idle speed way down. Sometimes that was low enough to stall the engines. Even then though, the scan tool would not lose communications.

I'm not sure what would cause this on your 2001. I suppose there could be a shorted sensor somewhere that when it gets to that test, it's drawing enough current that it somehow causes the regulators inside the PCM to stop regulating or something crazy like that, but it seems VERY unlikely.

Do you know if the scan tool was running an automated test, or just in datastream?

-Rod