So I have the dreaded "Monitors Not Ready" scenario. I just replaced my upstream O2s with new Bosch ones. I then put the old upstream in the downstream. I was getting a weird reading on Bank 2 Sensor 2. Since the readings were good on Bank 1 and 2 sensors 1 I figured why throw them away. All went well but I am getting the same readings (see picture). Now I know that Sensor 2s don't affect the emissions I would still like it to run correctly. Any thoughts? Oh and by the way Bank 2 Cat was replaced over a year ago but Bank 1 I think is OEM. Truck is a 2006 King Ranch 5.4 with 189K. Thanks.

 

The cat on bank 1 S2 is inert. It should be flatlined like bank 2 S2. That would indicate a properly functioning catalytic converter. Replace the cat.
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