O2 sensors on the exhaust manifold, these do the lean/rich for computer
Then for the cat converters you have
These tell if cat converters are cleaning up the exhaust
Bank 1 sensor 1 and 2 look OK
The bank2 sensor2 1.3v O2 sensor is for the cat converter is showing very rich
While O2 for exhaust on that Bank is showing very lean, so I would replace the Bank 2 sensor 1, it looks to be causing the computer to run that bank too rich, and that is causing the 1.3v on the cat sensor on that side.
It could be a vacuum leak on that bank, check the intake manifold bolts make sure they are tight, or spray carb cleaner around while idling, engine will change RPMs if it sucks in carb cleaner.
Exhaust manifold leak on that bank could produce the same thing, it sucks in air which makes O2 sensor see lean.
The Cat O2 sensors usually last the life of the vehicle, they get less build up since cat is cleaning exhaust up, hopefully, when it gets to them.
So only the front O2 sensors need to be replaced, my '94 4.0l still has original O2s, and they are still working fine, 300k miles
For the front O2 sensors you want a steady .5/6 while cruising
The rear O2s should be just below front O2 voltage
I would also check your scan tool on another OBDII engine, the idle O2 readings look odd
Last edited by RonD; 01-09-2014 at 10:10 PM.