'98 Neon and I just did the water pump (leaking seal) and timing belt, I had an issue with a squeak with a quick on and of throttle condition and was going to replace the exhaust do nut but when I grabbed the exhaust pipe and tried to shake it I heard a rattle inside the Cat convertor (not good) so I had a new one installed ($180.00 US). .Car as only 77,000 miles on her, anyone had this happen at this low mileage. I thought something must have caused it to come apart internally so I had a friend with an OBD scanner check her out, but no codes, strange.

 

if there was an exhaust leak the cat can be destroyed as the mixture inside will be too LEAN and cause the material to break down and burn up.

now that that doughnuts fixed this shouldnt happen again