Mine makes the noise when the AC is off so it's not that. I haven't had a chance to have someone pinpoint the exact location for me but it sounds like it's coming from the drivers side.
Since I only notice it after highway driving I'm not sure it's just a rattling of the muffler, otherwise I'd hear it even after city driving. Could it be oil pressure dropping?
Sorry to bring this thread back from the dead but I'm having the exact same problem. Ive only noticed it after driving on the highway for 20 minutes or so. As soon as I stop and let it idle the noise starts up and will eventually go away. Not sure what it could be. If I put it in park it goes...
