Which O2 sensor is the one that is upstream and on the right side? Is that the one on the branch of the y pipe closest to the firewall? Or is it the one on the branch of the y pipe that is closer to the front bumper? Thanks.....I am throwing code 04 09.

**also a part number if you know it...thanks

 

can someone please let me know....thanks

 

http://www.courtesyparts.com/A32_O2-sensors.html

is what you need I believe...

 

so I need the one that is closest to the firewall?....if so, do other people with fourth gens with y pipes have problems with this one going out because I replaced this one about a year ago which was only about 10k ago....is this right?

 

yes - the right side upstream sensor is closest to the firewall. Don't have any experience with the y-pipe mod and its possible effects....