It just started yesterday. A gurgling noise at idle, a deep noise in gear -- almost like a 350Z exhaust noise, only rougher. It seems like something is loose or broken. Any ideas?

 

CEL? How many miles on the car? Changed anything lately? Was it cold out when this happened?

 

Broken cat honeycomb.

 

That was my first thought, but its an 06 thats kinda young without some really high mileage. But if it turns out that the cat is bad I have one for sale currently

 

CEL? No
How many miles on the car? 77K
Changed anything lately? No
Was it cold out when this happened? No

 

I assume you've checked for leaks or perhaps a hole somewhere in the system?

 

I ran over something and the impact completely severed the exhaust pipe from the catalytic converter. Pasadena Honda said that it would have to replace the entire exhaust ($750), it's a wear item not under warranty, and suggested a muffler shop spot weld it. That's what I did ($50) and it's good as new.