Originally I thought it was the key and the keychain butting heads, but it's not.
It will rattle on anything except for smooth roads.

I didn't think I'd be bothered by rattles, but this one is getting annoying.


On a brighter note, I'm getting 33.5 mpg on mostly highway driving.
Only 500 miles so I'm still being patient before I take it over 4000 rpm.

 

Well... you could either try to figure it out yourself... or... take it to the dealer. It's brand new. There probably isn't much you can do about it yourself. It should still be under warranty since i hear talks of break in.

 

I had the same problem when I got my car, right off the dealer w/ 5 miles on it. I took it in and turns out my windshield was screwed up so they had to give me a new one. I'd say bring it to the dealer and go for a drive and indicate what is wrong with sounds like that it is hard to tell where it is coming from.