My CEL came on yesterday so I took it to Auto Zone and found out that one of my O2 sensors is bad. Where is the cheepest place to pick on of these up at? I dont know if they make aftermarket 02 sensors or not, I would like to stay stock unless the aftermarket ones are just as good.

 

Do you have a aftermarket Y-pipe?

 

No everthing is stock so far.

 

if im not wrong that the po140 code i think that means hes running lean i have that same crap but i got y-pipe and cat back exhaust, try reseting it, take the negative off for like 2 hours and see if it comes back on, i think thats the sensor that tells if the precats are working, is yours a cali or fed spec?

 

check oxygensensors.com i picked up a walker one for around 85 shipped after one of my primaries died after the header install.

 

there is a TSB for this that says to replace both banks downstream sensors. i did this and got the O2 sensors from oxygensensors.com, they give a 15% discount if you mention maxima.org and pay by money order, 10% if you pay by credit card. i got the Walker Universal ones p/n - 250-24000. you have to slice the wires and then reconnect the sensor, it is really easy (i think). i got both sensors for like $85 install took about 1.5 hours and i did it in the driveway on jackstands in the dark, the hardest part is getting the bad sensors out. be sure to buy a 22mm oxygen sensor socket if you do this yourself.