what do a bad catalyst converter sounds like and how much to fix.

What is your question?

There's a rattling noise coming from the vehicle after the vehicle runs for a while. The vehicle have a 119000 miles on it. No other problems except that.

What makes this problem better or worse?

Driving it for about a hour

How long has your 2011 GMC Terrain had this problem?

About 2 months. But I don’t really drive it