Noise like a rock hitting the car

I've had the same sound occur. I noticed it on cold mornings. However, mine was always when I was driving. I'm wondering if maybe it has something to do with how things contract and expand with temperatures?

 

I assume you two have looked under to see if anytging is loose?

 

My car has just over 1K miles and is babied. It better not have anything loose. But that being the point, no, I didn't see anything as I was checking for damage to my car after each time I heard it. Of course I can't crawl under the car to check.

I also have heard this while sitting at a light and no one was driving up beside me. We had been stopped for a little bit. Again, I only have heard this in the morning.

 

I've heard of mufflers and/or catalytic converters popping as they heat up. It's called "oil canning". I would suspect that it has to be something like that. It could even be the door skin.

 

That's what I'm going with.

 

Sorry, I didn't see/catch that you were not moving (darn smartphone).

Many of us '10s had under-covers coming loose and flopping and some dragging the oil change access door. First thing I think of when I hear "I heard noises".

With that said, I personally have never heard my exhaust system pinging or popping. Not like that ol' V8s did anyway, nothing that I would be able to hear from inside the car.