Rattling cause of muffler???

Ok heres my problem. I just got a 3A Racing muffler like a month and a half ago. But this past week i started hearing this rattling sound come from the rear of my car whenever my car shifts at near 3000 RPMs..everytime. But the wierd thing is you can only hear it when the windows are rolled up..you would think it would be the opposite cause the sound it outside of the car.

This is not the first time, a couple months ago i had to get part of my heat shield removed from the front driverside because it was rattling the same way, then it was gone. I didnt even know what a heat sheild was until it happened.

So my question it...does anyone ever had any problems with their muffler loosening things and then making noise??? Or is it just my car???

how was the muffler and whatever work done. i mean if the muffler shop or whoever did a half ass job then things might get loose. uhm check the muffler itself and how its hung maybe its moving to much or it could be something else. maybe get a stick or something and rev the car with the stick and listen around for the rattleing sound to pinpoint an area where u might hear the sound and look around there

yeah ill try to pin point it....but i think it might my heat shield...my mechanic will probably pinpoint it for me with no problem...thanks for the help

Ok, if you hear a rattling noise from the back, check the rear heat shield. Starts in front of the rear (driver side) tire. There is a braket there and if you mess with the rest of the exaust, this braket comes loose. You might have to visit the auto parts place and get a new bracket, brake of the old one or leave in place and tight the new one over it. I use the one from an old radiator hose after my son ran over a turkey( a real feathered one).