Was wondering your thoughts on changing the primary O2 sensor even though the MIL isn't on.

My 04 6MT TSX has 99k miles on it and every once in a while I get a nice smell of unspent fuel - usually after driving at interstate speeds and then slowing down. Acceleration is generally fine, but every so often I'll get a bit of a 'shudder' or 'not as smooth as normal' feeling - usually when the engine is cold. Also at lower RPMs when driving in rush hour traffic, for example, and I press the accelerator to speed up a bit, there is often a lag.

Does any of this sound like an O2 sensor problem?

Is this something I can do myself - or is it a dealer type of thing?

Thanks!

 

You won't get a MIL (Maintenance Indicator Light), you'll get DTCs in a P code format. Trust me, if one of the 2 O2 sensors were going bad, you'd have a P code immediately. They aren't something you want to proactively change either due to cost.

Smelling unspent fuel is something more around the combustion. You'd be better off looking at the spark plugs than the O2 sensor.