I picked up a 2007 A4 a few weeks ago. When I started it up to move it after snowblowing last night, it was making this odd thumping sound at the intake. Once the car warmed up, the sound changed. I'm assuming this is a turbo issue, but the "thump" seemed too slow for that. Thought I'd check to see if any of you guys have any input before I start tearing into it. Anything else I should be looking at?