Code p0133 o2 sensor help

[Jeepster78]

Hello my daughter has a 2000 jeep Wrangler 2.5 L engine check engine light came on. It’s getting the P0133 code stating bad O2 sensor. With the research I’ve done says it could be multiple things not sure where to start. Some of the articles I’ve read say to change the O2 ntk sensor, some articles say it might be a leaky injector others say, possibly a bad catalytic converter. Has anybody run into this code and can point me in the right direction and where to start to try to fix this? she needs an admission test and I don’t think they’ll pass it with the check engine light on with faulty O2 sensor code.
Thanks

 

[Steel City 06]

I would start with the most obvious, or the oxygen sensor. If you have time, you can unbolt the catalytic converter assembly to see if it is plugged or failed. Generally, when that happens you will either get a severe loss of power or additional codes.

If you have a scanner you can watch the LTFTs and STFTs to see how the engine is fueling. If they're off by more than 15% or so, something is likely suspect.