im trying to ref my 91 civic dx, it has a 93 b18. i have passed my motor inspection, but it keeps failing the emissions test. i replaced the cat, the cap and plugs. even seafoamed it. i need some help on what else i can do to make it run cleaner. please, any suggestions will help. thanks alot.
Mike

 

Change the O2 sensor, or oxygen sensor.
Replace the air filter if it's dirty.
Replace the PCV valve. This will just make it run smoother and not cleaner.
Replace the fuel filter, this will make it run smoother and not necessarily run a better emissions test.

 

When you fail the emissions test the guys at the emissions testing place give you a paper that tells you what emission you failed. Which emssion did you fail?

 

is CEL on ??
probably needs a new cat