How hard is it to replace the Oxygen Sensors on a 2003 Mitsubishi Outlander? The “Service Engine Soon” light came on and the dealer said it was the Oxygen Sensor… Can’t find a Service Manual.
You should have two, usually both need to be changed due to age. Not that difficult if you buy one with direct fit wiring. Most of the problem is getting to them and also possible rust depending on where you are located. You should check the location on your car and decide for yourself. There are online manuals you can subscribe to.