I have a 2000 TT with just under 36000 miles on it. Tonight, all of a sudden, as I was leaving an intersection, it started running really rough. When you give it gas to take off, you can hear a loud sucking sound under the hood. Kinda like it's sucking a lot of air but it doesn't want to move very fast. It seems to idle fine. Anybody have an ideas. Thanks for any suggestions.