I have a popping/clanking noise that is taking place underneath the car, maybe from the muffler for a few minutes after I turn off the car or when I am idle (I am not very savy with cars). I only have 1107 miles and this has happened since I got the car. Is this normal during the break in period? I haven't run over anything, driven her hard and have only used the recommended gas. This is for a 2014 RT classic v8 auto. I have an appointment with my local Dodge tomorrow, but any advice would be appreciated.