I've had that code in the past on an Accord. I replaced the catalytic converter and the problem was solved. You could try replacing the sensor first, that will help your fuel economy anyways. Anytime the check engine light is on more fuel is consumed than normal.

Your converter could be covered in the warranty. If not, this converter worked for me in the past, great price to if you ask me. I found this converter to be less expensive then a sensor at the time.

http://www.catalyticconverter.net/vi...t3.asp?pro=584