I own a 2007 GTI. This may sound odd, but when the weather is between 40 and 60 degrees outside air temperature, and I'm idling, the car makes a purring / rattling sound from the glovebox area. I've checked for causes from the cabin, and it leads me under the hood. I've checked for causes under the hood, and it leads me into the cabin. So it's near the firewall area. As soon as I touch the gas pedal, it goes away. Here's a short video of what it sounds like.
Any ideas? It's done this for the last 5 years, and doesn't get any better or worse.