Some models do have more than one 02 sensor, you can go to your local parts store and give them your information, their system should pull up the number of 02 sensors your vehicle takes for sure.
You may have two. One would be located before the catalytic converter on the exhaust, and the other after it. Sometimes you can see them by looking under the hood and under the vehicle.
To know for sure you should contact a dealer. If you had this problem diagnosed, they should be able to tell you which one is bad.
They can be expensive, so make sure that you're getting the proper diagnosis. Many times the O2 sensors go bad because there is another problem. Just so you know, mine lasted 18 years, it was in a Toyota. Good luck.
〉 Answered on Mar 18th, 2008 by Lori Johnson, Owner and Instructor at Ladies Start Your Engines