The CRV is putting out a 3rd cylinder misfire code but is running and shifting smooth, no other issues with it at this time. The check engine light comes on and off inconsistantly. Replaced spark plugs, came back on. What next?

 

Also: The front O2 sensor was replaced shortly before this started happening (1-2 months before)

 

Have you tested the ignition coil

http://www.obd-codes.com/p0303

 

Swap the coil with another one and drive untill the code comes back on after you clear it. If it's the coil that's bad, which it most likely is, the code will come back to the which ever plug you put it on. That's how you can confirm if it's the coil or not.

 

To add to the above poster, if you swap coils and the misfire is still in cylinder 3 swap the injectors and run it again. Like the coil, if the code moves when you swap injectors, you know it's a bad injector.

If it still doesn't clear then, move on too a valve adjustment.

 

Yeah if you move parts from one spot to another and then give the code for where you just moved it to, that lets you know that that part is no good. Because if it's not that part, it will stay at the same spot as before, so moving one thing did nothing, so you know that part is fine then.

It could also be a bad plug still, even if it's new, they could have been dropped. Also did you check you plug gap before putting them in? Because that will also cause a misfire if the gap is not set to proper spec. It should say what the gap should be on the sticker under your hood.