I have a CEL on my 2003 a4 1.8t. I took it to the mega auto shop today and the code came back that I my oxygen is too lean in bank one. (I asked her if it was to the right or the left, but she didn't get it!). anyway, looking through audiforums, it seems as if I have a vacuum leak.

There are 1,647 hoses on this car. (I counted!) each of which has at least two connections. How can I tell which one is the bad one? Nothing looks obviously bad......