Emissions problem?

[Brandonbennick]

I’m working on my wife’s 2011 2.4. Months ago I got a P0420 code. I saw there was a recall for the cat, checked with the dealer, they said we missed the deadline for it. Had a bad smell, rough idle. So I figured it was a bad cat, replaced it with a new one, plus both o2 sensors. Code went away, but then had a random cylinder misfire code pop up. I did plugs, coils, cleaned the MAF, throttle body and pcv tubing. Code went away but then there was a new one, camshaft position sensor. So I replaced both of those. All codes went away for a few months and it was running better than ever. Now I’m getting a P0420 code again with a rough idle. I’m looking for some insight on what else could be causing the issue. Thanks!

 

[swisscheese]

Do you have the excess oil burning issue? Could be clogging the Cat. I have the dreaded P420 also. I clear the code and it reappears about every 2 weeks. Mine still runs very smoothly with solid MPG numbers.

 

[comp]

what type of driving do you guys do ?? city/hyway,,,mix? how many miles a day etc, short trips are hell on cats and 02s,,,you use fuel system cleaner reg. ? quality of fuel ? buy at same station or just the cheapest??

 

[Gmcdean]

Try a cat cleaner. Maybe some junk left in there from before

 

[Gmcdean]

 

[pipwax]

I’m working on my wife’s 2011 2.4. Months ago I got a P0420 code. I saw there was a recall for the cat, checked with the dealer, they said we missed the deadline for it. Had a bad smell, rough idle. So I figured it was a bad cat, replaced it with a new one, plus both o2 sensors. Code went away, but then had a random cylinder misfire code pop up. I did plugs, coils, cleaned the MAF, throttle body and pcv tubing. Code went away but then there was a new one, camshaft position sensor. So I replaced both of those. All codes went away for a few months and it was running better than ever. Now I’m getting a P0420 code again with a rough idle. I’m looking for some insight on what else could be causing the issue. Thanks!

Did you ever figure it out? I have the same problem but no rough idle. It is running the best it has ever run.