Greetings ya'll,

So I bought a 98 Civic EX from craigslist from a janky salesman. Little known, I had to change the o2 sensors and the knock sensor. The CEL is off and there's no codes. My car failed smog once again and the smogsman made a suggestion(even though he's not suppose to) that it may be the Cat that needs to be replaced. He said that the smog readings where all over the place and never consistant. the first time he tested it failed the 15MPH test and passed the 25MPH one, and the second time it failed the 25MPH one and passed the 15MPH test. Any suggestions on knowning whether it's the Cat or if it could be something else.

Thanks for the time,

Dj

 

Hard to assess unless you post all of the emissions reports.

 

I worked on a 94 Accord with similar problems. Replaced O2 sensor at manifold per cel diagnosis. Exhaust leak failed it after that where there is a metal mesh like connector after the cat but before the muffler. Made readings vary.

 

thanks for the info, I will look into it.