Anyone running rich after replacing their secondary 02 sensor with a Bosch OEM replacement? This is the 4 wire 02 sensor?

The vacuum pressure is low and has left my rear bumper with black soot. Car is stock with 63,xxx miles.

Anyone have this problem? Other culprits?

 

Bump

 

Secondary O2 sensor is just to monitor the condition of the Catalyst material.

Its the Primary O2 sensor that controls how rich the fuel is.

 

Thank you for your input.