Loud Resonating Catalytic Converter on beater...

[Mark B]

Hey everyone,
My beater is giving me a headache. I have a loud sound coming from the catalytic converter. It sounds like echoing/resonating. The sound gets louder & more noticeable when the engine is under load, but it does make the sound all the time. I am assuming that the cat is hollowed out from the sound its making. It was making the same sound about a year ago so I put a cheap aftermarket cat on it and the sound stopped. But now the sound is back. Did I just buy time with the cheap catalytic converter or is something wrong with the engine that is causing my cats to go bad. I have another new cat sitting next to me that I am about to put on. This time I dropped $100 and got a catco direct replacement cat. I dont want this cat to go bad in a year as well.

Thanks in Advance,
Mark B

[TraceZ]

I discovered the cat on my V6 car was broken inside and rattling, so I gutted it.

The result was terrible. It sounded like a garbage truck, resonating very loudly. I scrapped the gutted cat and installed a Catco unit. It sounds like new now. I'm sure you will be happy after you change it.

[joe ws6]

im not shure but mybe the air pump. I believe thats what makes my 2000 t/a hawl. It pumps air into the exhust to warm up the converters quicker and make them work better i believe, correct me if im wrong. Mybe your air pump isnt turning off, if you have one that is.

[birdOFprey]

it could maybe be your oxygen sensors causing the rattling... i had a problem with my cats burning out too and it ended up being the MAF sensor was messed up and pumping through two much gas and burning them out...