Wondering if I need to change mine on my '95 Ody. How many of O2 sensors are there on the Ody? Guess I should start with what is the best source of info on this car for DIY maintenance. I do some on my '88 BMW 325 and use the Bentley manual, but with the Honda, not sure. Anyway, replacing the O2 sensor made a huge difference with BMW, and wanted to do same on Ody. Thanks for all replies and help.