There is a problem with the ford sending unit, you can buy another one from the ford dealer for about 10$. It causes teh symptom that on cold startups your oil pressure gauge sweeps on and off.
My '04 does it every time I go through the diagnostics.. I think I tried the HEC test the first time when I had less than 1k on the odometer.. I don't think it actually indicates the sensor is bad, it indicates that the cluster isn't receiving the correct signal from it.
Unless you're having a problem with your oil gauge, or your check engine light is on for that problem, I wouldn't worry about it. (Unless you're like me and just itching to fix something.)
The oil gauge is really annoying when it screws up through... just keep this in mind, if and when your oil gauge starts sweeping despite you having oil pressure, go to the ford dealer and buy a new oil sending unit.