I have a 1998 Honda Civic HX with a D16Y5 engine. My check engine light has been coming on periodically, with only the o2 sensor code. I got the part, but then the light didn't come on for awhile. Today I put some seafoam in the gas tank because the fuel system needs cleaning as well, considering chevron with techron kept the engine light off for awhile. After driving 20 miles with the seafoam, the light went off by itself, which has never happened before. So my question is...is my fuel system just that dirty or does the o2 sensor really need to be replaced?

 

If the sensor has not been changed in recent memory, I would change it. One less question mark hanging over our head, now.

 

if it went of by its self i wouldent worry about it that you prob just had some build up i have seen it happen many times