Dont know what it might be...could be my exhaust... i went out tonight and just revved it over and over till it hit 3....when i revved it using the engine rev switch (newb... dont know wtf thats called), didnt hear the sound, but when i got in the car, i could hear it again...it sounded like it was louder towards the bottom and in the front of the car...going to get it checked out @ the muffler shop tomorrow asap...anyone know what this might be in the meantime?

 

could be lots of things...most notably the heatshields on the exhaust. You can take them off or just bend them away from what it's hitting. I had a terrible rattle and searched for months but never came up with anything. Mine was actually the header bracket was loose. search the archives if neither of these are your problem.

 

cat heat shield

 

could be lots of things. heatshield loose, rock inside heatshield, loose bracked, loose connection at header or cat, etc. just put the car on stands and check the entire area. its probable an easy fix, just take a few minutes and check it out.

 

the heat shield got loose on my cat when i had my teg. all i heard was a rattle when revving, and eventually it just fell off. could be any of the heat shields on the exhaust though, check those first then go from there.

 

cat heat shield

 

cat went bad...replaced, problem solved