is this the upstream or downstream 02 sensor????

 

Downstream O2 Sensor Stays On At Center

 

had a brain fart and couldnt figure out which one[&:]
problem is that the wifes car is running horrible
has a bad idle and runs kinda rough.....didnt think it would be from the downstream 02 sensor
for sum reason it was throwing a code for the tcc, and the egr...i replaced the egr and the 02 sensor was next on the list