Rattle, what is this rattle? Options

[Euphoria]

Hey, had a rattling problem somewhere in the exhaust recently which I believed was the flex pipe, had it replaced and the noise is still there so I'm fairly sure its the cat, now as far as I can see in the Australian ST204 there is only one cat which is on the manifold? so I looked up on Ebay and they seem the most expensive ones and as for getting them in Australia I'm sure they are super expensive so I have a couple options.

I looked at my friends mums celica recently and noticed it had headers and where my cat was, it looked to have none and the o2 sensor was lower, why is this? would there have been a cat in there that couldn't be seen perhaps?

another option is perhaps gutting the cat until I find one at a wreckers or something, I've heard people say this lowers power and makes it louder, I've also head it makes it no louder and no more or less power, whats really the answer?

thanks, this is driving me crazy.

This post has been edited by Euphoria: Apr 12, 2010 - 11:30 PM

[Euphoria]

well I picked up a stock manifold and cat, noise still there! so I don't know where to start, what else can cause rattles?

It rattles at specific revs, you can't hear it directly in front of the engine as the engine noise overpowers it but you can hear it in the car with the windows down coming from the engine bay area, you can even hear it outside the car, im so sick of it haha.

Anyway engine mounts could cause this? the front and rear have been replaced but the other 2 I haven't touched nor looked at.

thanks.