on my driver side cat, it rattles like a metal ball in a tin can when the Car is idling (intermitently).

I can also duplicate the same problem when I just bang on the cat with the engine off.

I am writing to see if anyone has experienced this or if my Cat is really blown... Please advise before I take my car into the shop to have the CAT removed and looked at.


Thanks in advance,

P.S. I have elminated the possiblity of the CAT banging against the heat shield

 

It could be that a piece of the cat broke off and is rattling around. You should take a look asap. If that piece is big, then it will continue to rattle around and eventually form into a perfect ball. When that happens, it will intermittenly plug up the exhuast outlet. So when you hit the gas, it plugs. When you get off the gas, it unplugs.

 

Sounds like you need a new CAT. At least thats what I have done when it has happened to me on past vehicles. Unfortunately, they are not cheap. Relatively speaking.

 

ya the plantinum is gone in it

 

time 4 racing kats!

 

Lol... the funny thing is, I just took my Kinetix off last month and sold it to my friend. However, can you please explain more on your principle of "when you are on the gas, it plugs; when you are off the gas, it unplugs... you should have it looked at asap before it becomes a perfectly round ball".

Please pardon my ignorance on CATs, I just can't visiualize how can a honeycomb be causing the problems that I have now; is it some part of the honeycomb got destroy? but won't that be blown out of the CATs? (at least to the Ypipe...)

I really appreciate you guys' help tho.
Kudos!

Edit:
I will have my car looked at again on monday and very likely replace the rattling cat with my friends' stock CAT... but is wondering if it is okay to drive the car over the weekend.

 

Um it was me that said that, not him.

Imagine a big chunk of the honeycomb breaking off. Then it rattles around when you drive. all the sharp ends get broken off and shoots out the exhaust. Eventually it forms into a ball. I've seen examples of this in an header shop that I used to go to. Now if the chunk gets small enough, it will just pass though. But if it's big, the ball will get pushed against the outlet of the cat (ie.. a circle), when you hit the gas. (increase the exhaust flow). When you let off the gas, it creates a vacuum condition and sucks the ball off the outlet. This leads to some very odd running and is hard to diagnosis

 

Thanks for the explanation bro, let's keep fingers crossed for my cats..and that they can wait till Monday to be replaced :< I have heard some weird sound recently around the CATs but didn't hear the Tin Can rattling that I have now until few days ago.

Thanks again Jeff