Could it be your Aero Shield panel? I heard a flapping thumping sound from underneath the car. I didn’t know about the shield sections until I evidently ran over a curb and shredded a section. Tesla service charged me $200 for the repair that I thought should be under warranty. Yesterday I hit a pothole that shredded TWO tires, maybe damaged the rims. I purchased this M3 in June 2019. I think it may be ji Ed.