Catalytic converter

Why did you replace it in the first place ?

Downstream should not be a mirror of the upstream sensor, if the converter is working right the downstream should show a much lower variable voltage at full operational temperature

To get more accurate, this issue is on a 06 lincoln navigator 5.4l. Cats were replaced because bank 2 cat disintegrated. I'm sure it was do to the air leak on the rusted weld that was on an inlet of the cat. However the basic tune up was completed before installation of bank 1 and 2 cats (spark plugs, coil packs and ohms checked out on all fuel injectors) I understand that downstream o2 sensors should not be mirroring upstream. But the question is why am I now on over 1000 miles and no codes are popping up. 4 not ready o2 heater, o2 sensor, cat, and evap. I just read that some people had exact same problem and the culprit was a malfunctioning "Fuel pump driver module" I will look into that tomorrow and will update. I will also check all the fuses as the research suggests that could be a cause as well.

The O2 heater must work, so if the fuse for the O2 and the heater is not blown and the wiring checks then most likely the O2 sensor is contaminated or just bad. Now the EVAP code is most likely the control valve but I have also seen damaged hoses, so check them out all the way. The catalytic code usually means it’s not getting up to temperature to function, now that could be to lean a fuel air ratio possibly from the EVAP problem but as you said fuel control, pressure and flow.

For all the readiness monitors you mentioned to set the gas tank must be between one quarter and three quarters full. If the gas gauge is above the three quarters mark or below the one quarter mark those readiness monitors will not set no matter how much or how far you drive. Hope that helps! Jim