OK Ive had this problem as long as Ive had the car but now I figured ide post it cause im bored. So like when my car idles I can hear this ringing or rattle from under my car I think its a flange thats holds the different section of my car togeather cause I can fell air leeking from there. I dont know for sure what the ringing is, its comming from somewhere in the middle of my car, anyone know.

 

exhaust leaks make kind of like a clicking noise. I thought my turbo was making the noise,but found one of the gaskets blown.

 

jack the car up and see???

 

Briefly block the tailpipes with your hand, if it gets louder when you do that you have a leak.

 

listen for tapping noises = exhaust leak

 

Almost ten years ago, the lower heat shield of my OEM cat cracked. The noise it made was simular to what you are describing. You may wish to unbolt the lower heat shield and see if the noise disappears.

 

I think you may have it for 500. I think thats exactly what it is. Its right by my cat and I can feel like air comming out of it, Ima try what Ronin said with my hand just to test it, it doesnt make any clicking noises, just a constant metal rataling underneath my car. So what should I do if it is the heat shield, just replace it?

 

I just took my lower heat shield off and hung it on a rack in the garage. It could be useful if I drove over dry brush with a hot cat, but that never happens, so I don't really need it. If you have it welded, it may crack again. I tried having a cracked heat shield welded on another car, and it cracked again in no time.

 

OK cool Ill take a look at it, most likely remove it if its the problem.