how to tell if oxygen sensor has gone bad

[RocketandRollit]

If you are using TuneBoy, in TuneEdit open the edit tab, open tune constants and make sure the box that says O2 sensor fitted is unchecked.
This way, the O2 sensors is ignored, working or not.

 

[RocketandRollit]

Check your version of TuneEdit (help, about TuneEdit...)
Mine is version # 3.9.1.6.
If yours is older, download a new version.