Muffler making noises?

Question

Sounds like grinding/screeching noises from muffler whenever I press on brake and idle. It only comes from left muffler. So today I took off my muffler tips and drove and still the same sound. I put it in park and left the car running it sounds like tapping noises in the muffler. No sound while driving only at really low speeds.

Answer 1

My guess is a broken motor mount. Look at them and see.

Answer 2

Check for exhaust leaks.