Some useful information on O2 sensors, that may help us make a wise choice for a replacement & why that wise choice may be the OEM sensor. A number of design parameters & computer programming, ect are explained. http://www.babcox.com/editorial/us/us80159.htm

 

Understading that there are a lot of older Rangers out there this is good information. This was written in 2001 notes that obd11 sensors will last longer. So be aware that before 100,000 miles its not much help to replace them just for fuel mileage on obd11 vehicles.
Dave

 

Good info pawpaw, thanks!

 

BUMP:

Ran across this O2 sensor TSB, that sorta fits in with the O2 sensor mini tutorial.

https://www.ford-trucks.com/tsb/full...hp?tsb=*01-9-7

 

Ouch, now my head hurt.

It's a good arguement for using the local best service available, Ford Technician.
There's at least one everywhere.

 

O2 sensor contamination read photos. Tomco Inc. Have a look at these deposits to determine what killed your O2 sensor.