This was kinda the same problem im going through right now to, some times it'll feel sluggish but then other times it'll feel normal. I only have 46000 miles though? Could it be the timing belt? Tune up? How the hell can you find out whats wrong other then going and blowing $300 dollars.

 

I just spoke with my local Audi service department, he told me that my problem sounds like a faulty or sticky DV valve. How long does a stock DV usually last? I only have 45000 on my 2001. You think there could be truth behind this? Also I asked about a freaken tune up, $234. I asked what it included he said labor and spark plugs that's it. I'm kind of new to Audi's but is every service an outrageous price?