Honda Repair: O2 Sensor/Fuel-Air Ratio Sensor, o2 sensors, auto parts stores

Question
I have a 2003 honda accord 6 cylinder in which we are getting horrible gas mileage and the check engine light is on.  Could this be o2 sensor or either fuel-air ratio sensor, is there a way to check it before buying the parts and there is some argument over where they are located and how many there actually are

Answer
Sheila, take your car to an auto parts store and have them run your check engine codes. Usually a free service. Or take it to the dealer to find out for sure 100%. Should be free too? You have an OBD-2 vehicle so most auto parts stores should have this diagnostic tool. I think you have 2 O2 sensors. The diagnostic will tell you if one of them or both are bad. Whichever the O2 sensors are locted in or near the catalytic converters. Fuel/air sensors dont fail to often but i guess it could be the problem.