Hey Everyone, I currently drive an 06' scion tC. I've been getting a sort of rattle whenever I stop at a light while idling on "Drive" . But when I drive it fades away. But at certain RPMs, you can hear the rattle underneath the car. It kind of gets annoying because I feel like its much louder on the outside of the vehicle and don't want to get pulled over for it. The only modifications I've done is got a Spec D Tuning exhaust. I've read a similar post saying that it could be a water pump problem or a heatshield tapping the exhaust pipes. Down below I will attach the video of the sound from my cabin.

https://youtu.be/LuOhzrY-N5M