I've had a check engine light for months for bad cat (catalyst system below threshold efficiency) and 5 days ago my car rattled, with the car off, i tighten the bolts around the cat... and i tried shaking it, I heard it knock inside, and I had tapped it a few times to hear if it rattled and it didn't do ne thing, I ran the car, and the cat became clogged! I lost top end power like crazy, and slow as hell on the revs at 4,000+RPM... and the exhaust sounded like stock... I drove it like that a few days, tried punching it hoping my cat would shit itself to pieces and it didn't happen. 2 days later, I tried driving at the RPMs which the exhaust would rattle most, and I guess it helped break down catalyst material I saw some stuff inside my exhaust it looked like ashes ,some lil gray looking rockz and water inside.

Each time my car would get a lil louder every day since then, and 2 days after seeing that stuff in the tail pipe. The check engine light disappeared while i was driving I was like

Now tonight my car feels back up to speed maybe even has a bit more torque than before it feels like. Has anyone experienced this on their cat before? I mean it took the cat to shit itself some to get rid of the check engine light?

I'm glad I don't need to buy another cat... so I guess maybe sometimes you need to ding it a few times if you got that CEL and let the cat crap out.