Before sending it to Ford, which will just replace your O2 sensors, I would suggest trying at least these items.
�· Contaminated HO2S sensor or connector (coolant, water, silicone, fuel, oil, etc.)
Clean/dry the connectors.
�· Blown fuse
Fuse 13
�· Low battery voltage
Check battery voltage, engine off, lights on for 1 minute, 12 to 12.2 volts for battery.