P0430 mercury grand marque 2004

Question

where is the 02 sensor located upstream on 2004

Answer 1

you need to check bank 1 and 2, Sensor 2 that is the one that reads the catalytic converter is not working correctly and sets the P0430 and P0420 

 

They are located under the car 

there is a recall for the catalytic converter, not sure if your car applies you might have to call and check

(800) 521-4140