2005 Ranger 3.0 fuel mileage

[Lakewind]

Horrendous fuel mileage.....My 2005 Ford Ranger 3.0 was never a champ at fuel mileage getting 20 mpg on the interstate but its dependability and longevity made up for it. However, 26 years and 275,000 miles later my little dependable Ranger is getting 15.4 mpg @ $4.29 per gallon. Ouch! It's always been maintained. Has anyone had any luck getting their fuel mileage back? Could O2 sensors cause this? Any feed back is appreciated. I've changed plugs, wires, coil pack, electric PCV valve in the last 2 years. Fuel and air filters always replaced. 3000 mile motorcraft oil and filter changes. The truck runs perfect.

 

[SenorNoob]

I have heard that O2 sensors do wear out and tend to cause the vehicle to run richer as the wear. I'm guessing it's kinda like incandescent bulbs where they actually get dimmer as they age.