It failed emission 2nd time. It's producing too much carbon. It's reading .92 where it needs to be .71. I already changed out plugs, wires, pvc valve. After all these have been replaced, I pired in some "Pass Emission" chemical and drove for over 250 miles but the 2nd test came back with the same exact reading.
My next step is to change the Oxygen sensor.
It has no CEL on. It passes the fuel cap test.
Is there any thing else I need to clean? I will clean the throttle body this weekend when I change the O2 sensor.
It's a 94 Accord LX.

thanks

 

If the O2 sensor doesn't fix the issue I'd guess a new cat would.... but that's just a guess as my state doesn't have emessions tests yet...