Ford Repair: 1999 FORD EXPY, 4X4, oxygen sensors, gas mileage

Question
How can I check the oxygen sensors on my 5.4l for proper operation? I don't have much in the way of symtoms other than low gas mileage, 14 avg.

Answer
The computer in your Expedition monitors the engine functions for optimal fuel efficiency and emission control. If a problem developed that affected the sensors the check engine light will come on and set a code. The best way to monitor the sensors yourself is with a scanner. Keep in mind that unless you know what the numbers mean seeing them will not help you understand what the numbers are telling you.

Unfortunately 14mpg is probably not a bad figure for an Expedition 4X4