@
Ultramaroon No, stock. Both times were from coming off the interstate after a 3 hour drive and driving around 30-35 mph in 3rd gear, rattle like my cams were woodpeckers. It could have been that I was low on oil, since my first year I spread out my intervals sometimes to 8000 miles. Haven't had it happen since 2013-14, but it's definitely abnormal when it happened.
The 2nd video that @
rburrow87 made shows it perfectly, though in my case my sounds were lighter since I was just cruising and maintaining speeds 30-35, and when I'd reach a certain rpm it would rattle like that.