Hey everyone, I need some help. I recently bought a 2008 tundra with the 5.7 and today I got the famous ( or so I heard ) P0420 code. I am the second owner and the truck has 160k miles on it. The only upgraded part I see is the TRD cold air intake. I drove 20 miles to the store (mostly highways) and when I was finished shopping I started the drive home and within 10 miles I noticed the check engine light. I read that it could be due to a dirty air intake filter, a bad MFC sensor, a bad O2 sensor, or a back CAT. Now which is more likely the cause? I haven't noticed any power loss or bad smells while running the truck since the code and the dealership I got it from should have run emissions on it ( they said they did at least ) so it couldn't be that the CAT is bad right? It would have failed emissions. I will appreciate any help, thank you in advance.