when i start my camaro i can here my exhaust rattling. my dad says that it might be the muffler geting ready to take a ****. i looked and its all tight the exhaust is not loose. once the car starts moving it goes away. soooo my question is, if in fact it is my muffler, when i go to replace it can i get a little more sound out of it?

 

Check the various heath shields around the exhaust stuff. They tend to rust and rattle. Otherwise, I would suspect the cat more than the muffler. The ceramic honeycomb inside the cat can break up and rattle around.

 

if it is the cat do i need to replace it? both of them are in the front and the sound is in the back.(sorry i didn't say that before), still the cat?

 

Like Pete said, check the heat shields.

 

I get a noise, more like a ringing. Its coming from the 02 sensor, there is a ring around it that vibrates.