possible cat failure ?

[Accord07]

hey guys,
whenever i accelerate, you can hear something shaking in the front...or rattle. it only happens at idle speeds, and sometimes when accelerating. Could the cat have died ? some people say that the rattling means it needs to be replaced.
ill try to record a video of it rattling.

[visualpoet]

I'm going to say it's probably not the cat. The cat is under the car and behind the motor. You might be hearing valve noise, rod knock, exhaust manifold shield rattle. It's impossible to say without hearing it.