A mammal? What? Since when do mammals rattle? Catalytic converters don't rattle either. The heat shield on them does occasionally.
Have the car running and peek under. Heat shields are usually thin aluminum sheets bent around hot parts like your muffler, catalytic converter, or other exhaust components. None of them should move.
It sounds like the Catalytic Converter is gone. When they go parts of the netting 'blows up' and it rattles around at idle. But when you accelerate, it disappears because the exhaust 'pins' the innards to the walls of the converter. Another thing could be a heat riser of the headers. They control the heat sensor and allow better fuel air mixture to the throttle body. They do tend to rust. Take it to a muffler shop and see if this might be the problem.
it's probably a small mammal.
PROBABLY the brake "pads" are worn out .
I have a 2003 Camry me with about 200,000. For a little while now I've been hearing a rattling sound as I'm on the brake. When I'm accelerating and driving it's completely fine but it's only when my foot is on the brake and its in drove or reverse that it happens. But when I'm in park for the most part it doesn't sound. I would bring it to the mechanic but I want to see if there is anything I can check before I spend money bringing it to a professional. Thank you very much for your responses !:)
