suddenly the car starts getting really bad mileage (270 all freeway miles and light comes up)... ** i can get 280miles mixed driving

before:
300mile freeway
240mile city

now:
270mile freeway
210mile city

anyways, ive always thought they were 60$ or so. courtesy is selling them for 110$. how much is labor also?

i got my bosch one from checkers for about 60 bucks, it works well..

I just bought mine from Autozone for $61.99 + tax

It's the same one as the one from Nissan. It's an OEM part made by Bosch.

Also, in terms of installing it, you can do it yourself. Here's a link to the threads regarding the installation procedure:

http://www.sr20deforum.com/showthread.php?s=&threadid=13000&highlight=oxygen+sensor

Here's one with a few other tips about replacing the O2 sensor:

www.sr20deforum.com/showthread.php?s=&threadid=26346 (http://www.sr20deforum.com/showthread.php?s=&threadid=26346)

Hope that helps.

$64 @ Napa Auto Parts, Easy install. Works fine.

Q in Sac

$60 from Advance Auto Parts. Very easy install when you have a header.:D