I have what looks to be long strings of fiberglass coming out of the tail pipe of my 94 Mazda (only 54k miles). I assume this is part of the muffler coming apart. Is it safe to drive this way (i.e., worried about exhaust backup) or should I replace it.

That’s the insulation from inside the muffler coming out. Should you replace the muffler? Well yeah! It’s coming apart on the inside.


Tester’s right, but it’s not an emergency - if you feel a strong flow of exhaust out the pipe, you’re not clogged up. Also, get a good quality replacement, the super cheap ones can hurt mileage.