Its a 2000 Civic Ex. 135,000 miles.
We got a code 67, cat efficiency missed....and so the first thing we did was replace the secondary o2 sensor. The code came back so we went ahead an put a new cat in. (it was the eastern catalytic one)...the code 67 went away, but after about 200 miles, we got a code 63, (secondary 02 sensor circuit)....pointing to a bad secondary o2 sensor, but we had just replaced it 500 miles ago.
Since we had to remove it and put it back in when we put the new cat in, I checked all the splices we made, and re did all of them in fact. Still, getting the o2 error.
I suppose I should buy another secondary o2 sensor, but does it make sense that it could fail so soon?

Thanks in advance for any input!
Neil

 

Hmmm...

 

If you bought the correct secondary you wouldn't need to splice.

 

Yeah, here we go......
thanks anyway.