[JW657]

That was my next thought, a cat breaking up internally. If you cant find the source shaking and tapping underneath, might try a local mom and pop muffler shop to investigate. Theyre usually pretty reasonable moneywise. Maybe have them diagnose and fix depending on the cost, or you do the repair if able.

If there's one thing I hate doing it's exhaust work. I try to source all of that to my local garages.