That's what i thought and brought it to the dealer, they checked evrything under the car and found nothing.I also wanted an oil change so when they do oil changes they also check the tire pressure........Mine was at 50psi!!!
And there was my problem, they deflated all tires to 32 psi and my car is alot smoother and guess what???....rattling is gone! So check your tire pressure and make sure it's at recomended psi for your tires!