I'm looking for some feedback from anyone who has changed the oxygen sensors on their truck. My Ranger has 112k on it now and I've been considering changing them, but I'm wondering if it's worth the trouble/expense. Did your truck run better or get better fuel mileage afterward?

Popular wisdom says to change them after 100k. I've noticed that my mileage has dropped 1-2 mpg in the last several years, but my driving habits have changed since I moved, so I can't be certain what is the cause for that. The truck does run fine.

Looking at how everything is installed, I'd say that disconnecting the electrical connectors will be more difficult than unscrewing the O2 sensors. A couple of the connectors look to be snaking over the top of the tranny where you can't see or access easily.

 

If the mileage has in fact dropped off significantly, that could be a factor. Maybe clean the MAF sensor and install a new O2 sensor and see what's what. It won't hurt anything that's for sure.

 

I would scan it first to see if you have any codes.. If you do have to change them,,Auto Zone has a rent a tool thing and you might want to make use of that..I got the tool and had to apply a little heat after disconnecting wiring with a hand held propane torch and then it came out..when reinstalling new one use a good anti seize product and apply to threads making sure not to get any on sensor..There are at least 2 or maybe 3 sensors,,,located upstream and downstream 1 behind and 1 in front Cat Converter,,if they check bad make sure to change them all...With over a 100K on them they are due to be changed

 

I just got done 2 weeks ago changing all 3 on my 2003 Edge 3.0l. The forward one is a B**** to change, very tight access. Hard to disconnect the electrical connection, let alone breaking it loose from pipe. But, yes it is doable, just have a lot of patience and the right tools. I bought a long 7/8 wrench to break loose the forward sensor and I had some long hose pliers I used to disconnect the wire. But got her done!

 

There really is no scheduled replacement interval on the O2 sensors, although some people prefer to replace them around the 100K mark as (probably) a preemptive strike to prevent damage to the cats. What you can do is use a decent scan tool (or a quality DMM) and verify correct operation of your O2 sensors (look at the voltages produced by the sensor), thus eliminating the need to replace a part that most of the time, is a life of vehicle item. When doing this, remember that the PCM commands the voltage swing and the frequency of the swing will be much more frequent on the front two O2 sensors (~1 second, in general) than the rear. This assumes a vehice in good running condition, of course.