02 sensor

[Guest]

I have had my car for about a year and a half now and the 02 sensor has never been changed and I know my mom never changed it when she had the car. How can I tell if it needs changed?

Also, what is the best brand of sensor to buy. Bosch is the cheapest at like $50. Im sure that would be a good brand right?

[Guest]

I replaced my O2 sensor last year.  BTW, if you have an OBD-2 car you have 2 O2 sensors, one post-cat and one pre-cat.  To know if you have OBD2 or not look to see if you have a MAF sensor right after your air cleaner box.  It is a square peice of metal with a plug in it.  Mid-95 ad after Berettas have OBD2.  Anyways to your original Q...O2 sensors should be changed around 50K miles regaurdless.  Some sypmtoms of a failing O2 sensor are bad gas mileage, and possibly your check engine light will come on.  I diagnosed mine with the terrible gas mileage i was getting.  I bought the Bosch brand and had no problems with it.  It was around 55$.  The one that comes after the cat. is more money:( .