There's knocking loudly and muffler sounds loud as I'm driving and the catalytic converter sounds like something is loose inside of it.
Aug 27, 2023 at 6:06 PM
Advertisement
STRAILER
✓Experienced Mechanic
55,604 POSTS
2020 GMC JIMMY? This happens when the catalytic converter is hot and then water gets slashed in it which breaks apart the honeycomb inside the converter. This means it will need to be replaced, here is the new catalytic converter on amazon for $135.00 I believe.