I have a brand new 2005 A4 convertible. I bought it 19 days ago. It currenly has 1800 miles. What I think is the vaccum hose associated with the turbo in the very front of the car has come off three times. The first time I was 3 miles from the dealer and they thought it wasn't tightened properly. It's since come off two other times and I tighted it down myself each time. Typically 3-4 days later the check engine light comes on. I've had it back to the dealer and they claim that the codes associated with that light are from this vaccum hose. The dealer has been no help whatsoever -- simply clearing the codes associated with the light and re-tightening the hose. I'm picking up the car today for the third time and am certain I'll be back in the shop within 2 weeks. Anyone have any idea what is going on here? Thanks in advance.