My 07 MC just had its Catalytic Converter replaced. I first noticed that there might be a problem when I drove over Tioga Pass (9945' elevation) on a recent road trip. It smelled like burning paper and when I stopped the car it was ticking a lot from the exhaust area. I know it was a long steep road in a quite high elevation, but I would think that it should be able to handle it. Anyone else have a problem with their CC?

 

There was a bad batch of cats mid-07. If yours was one of them (sounds like it) and it got replaced, you're good to go now. Enjoy the cleaner air.

 

Just checking in, I just got my catalytic converter replaced (today) as well. The dealer also replaced the oxygen sensor. I'm around 12k miles. Hopefully this will fix the problem. I have a 2007 MC - bought in December. Here's a few more threads on this issue:
https://www.northamericanmotoring.co...d.php?t=134593
https://www.northamericanmotoring.co...d.php?t=143262
https://www.northamericanmotoring.co...d.php?t=150147