O2 sensor or something else?

[smurphy]

My son's jeep has a p0420 code bank 1 upstream catalytic converter not in range. From what I found out so far is it could be the catalytic converter or just the 02 sensor. Any other possibilities? And should I just replace the 02 sensor and go from there? Or anything else I should consider. It's a 98tj 2.5l 5 speed.

 

[Jerry Bransford]

If the engine runs worse after it starts warming up that's a good clue the upstream O2 sensor is bad. If not it's hard to say.

If you replace it, go only with an NTK O2 sensor. Don't install install a Bosch.

 

[smurphy]

It runs and drives great. No issues when warmed up no rough idle no loss of power.

 

[Jerry Bransford]

Doesn't sound like a bad O2 sensor then. Your TJ has just one catalytic converter.

 

[smurphy]

I believe so. I'll get a good look at it tomorrow. I know it has a newer exhaust from the cat back.