CEL p0421

[kamon8404]

I know that P0421 has something to do with the cat. I have an ion tbe with a high flow cat. I doubt that something is wrong with the cat. Do you guys think i threw this due to not letting my car warm up enough and driving in the cold weather? (its has been as low as 7 degrees here recently)

[BOOSTR]

Sometimes a few successive cold starts can trigger it, however the cat or O2 could also no longer be functioning or a spark plug could be fouled. I'd check the condition of the plugs and clear the pcm. If you have high mileage than you may want to just replace it as its the more important of the two oxygen sensors used by the pcm.

[kamon8404]

Yeah I cleared it and have let it warm up before driving each time and it has not came on again (2+hours of driving). I'm gonna check the plugs but I did just put them in not even 10k ago. I was planning on new coils and wires soon anyway so i'm gonna go head and get plugs too if i need em.