So I'm driving on the highway this morning in my '05 1500 QC Hemi and the check engine light comes on. Made sure my gas cap wasn't loose, restarted the truck a couple of times, light still there. I hit a dealership local to where I was at the time and they squeezed me in. The service manager said that my catalytic converter is bad. Here's what the dealer diagnostic summary said: "Code P0420 Catalyst 1/1 Efficiency Order Cat. Converter O2's switching properly, no obvious converter damage, no exhasut leaks"

How can the cat go bad after only 5100 miles? Does this seem right? I swear the engine seems a little sluggish now, the exhaust has a slight sulfur odor to it and the rattle/vibration I've had lately at certain speeds/RPMs is getting longer and louder. This phenomenon started after I put the Mopar CAI in but it's been getting noticeably worse, don't know if it's related to the cat. I still have the stock exhaust system. Any ideas? Have others seen this problem?

 

Sounds like you got a bad cat from the factory. The sulphur smell is typical of this. Factory warranty to the rescue

 

The odd thing is ever since I went to the dealer, the light hasn't come back on. I specifically asked if once they hooked it up to the diagnostic that the light would clear and the service guy told me it would just come right back. Well, 60 more miles logged on my truck, light has yet to come back on. Sulfur smell still there, still seems sluggish to me but no light. I hope my dealer doesn't give me any crap Monday morning and say that this other dealer must've made a mistake and try to send me on my way. I guess this might be the right time to have that cat back Borla exhaust dropped in if the truck is going to be on the lift anyway getting a new cat!

 

The odd thing is ever since I went to the dealer, the light hasn't come back on. I specifically asked if once they hooked it up to the diagnostic that the light would clear and the service guy told me it would just come right back. Well, 60 more miles logged on my truck, light has yet to come back on. Sulfur smell still there, still seems sluggish to me but no light. I hope my dealer doesn't give me any crap Monday morning and say that this other dealer must've made a mistake and try to send me on my way. I guess this might be the right time to have that cat back Borla exhaust dropped in if the truck is going to be on the lift anyway getting a new cat!

 

It's why we have a warranty. Massed produced parts can never all be flawless.

Good luck.

 

Besides, they may not "want" to do warranty work, but they still get "paid" from warranty service, just not as much as if you walked in off the streets. I have yet talked to a service tech that didn't want to get paid.