Hey wassup guys. About two weeks ago I filled up my tank and got a check engine light after about 10-15 minutes of driving. I didn't have a scanner but i assumed I didn't close the gas cap tight. So I reset the computer. After about 3 days it came back. I was able to use a scanner and I was receiving a P0420 Catalyst system efficiency below threshold DTC. I noticed I hadn't changed my CAI filter and it was black which means I was probably running rich for a while. Which I now beleive might have cause it to go bad. I've had the cat for about a year and a half. I only use 93 octane fuel, typically Amoco. Anyone had a similar problem? I'm probably going to take a look at the cat this weekend, but I guess I might have to end up changing it. Any info would be appreciated.

 

Take the cat out and look at the 02 sensor. If you were running rich, there should be black carbon deposits on it. Try cleaning it and reinstalling it. If there is a rattle to go along with it, then the catalyst has come loose.

 

Is there some kind of cleaning kit of sort? Thanks for the info. I'm going to take a look at it this weekend.

 

I HAD THe SAME PROBLEM...if u check 2-3 weeks back on my post I had a CEL 420, which the dealer told me it was a bad cat. I also have a carsound cat from IPSRacing. I reset the ecu and it went away, but now my Apexi N1 is not loud anymore, so I figure the carsound cat is fried which is not letting the air threw efficiently..I'll probably take the cat out by this weekend, and I'll let u know.....I think its a common problem, i think a test pipe is better in my opinion which I wil be changing to if my cat is fried...

 

Even though I reset mine it came back. But I guess after running around with a dirty CAI filter for a while the extra fuel I was dumping might have ruined it. But if we go test pipe the check engine light will stay on won't it? Plus I believe the decibel level will go up considerably. Keep me informed.