i previously failed a smog test in california(who doesnt)..car is a 1992 honda civic dx...the smog tech said it could be the O2 sensor or something else here is my question...

there was improvement between my 15 mph test and 25mph test... here are the numbers for both. also i put fuel system cleaner in about 20 miles before i went to get smoged on an empty tank then filled it up just in-case that would make any of these numbers jump that much just an fyi..

15mph (1640rpm)
HC (PPM) Measured/Max allowed 226/92 (failed).... CO (%) Measured/Max allowed 0.65/0.55 (failed).... NO (PPM) Measured/Max allowed 716/2862 (failed)

25mph (1778rpm)
HC (PPM) Measured/Max allowed 129/57 (failed)... CO (%) Measured/Max allowed 0.18/0.38 (Passed)... NO (PPM) Measured/Max allowed 442/764 (Passed)

what could this be? the reason im asking is because Cats are expensive as hell for california so i want to make sure thats pretty much it before i go that route...

Thank you for your time.

 

Don't start new threads about the same problem.

Another hint you could unbolt your cat and see if someone has hollowed it out. If so of course you need a new one.