Pulled the plugs today and swapped in my older distributor cap. The car got a little better with the older cap, but not much. Four of the plugs are a tanish brown colour (like that of coffee with milk), but the other one {cyl. #1} was black. Not wet or oily, but black. Another thing I noticed was that all of the plugs except cyl #2 had backed out and were loose in the head. I also found a definite vacuum leak/issue.
<img src="http://pictureposter.audiworld.com/70163/audi_plugs_006.jpg">
That was taken with the engine idling. If you snap the throttle open and shut the hose blows back out, then gets sucked flat again. There's also a crack in that hose that whistles.<ul><li><a href="http://forums.audiworld.com/4000/msgs/83108.phtml">My original thread.</a></li></ul>

I found that piece of hose laying in the trunk when I bought the car, I had no idea what it was, but I kept it. Good thing, because on the weekend, I noticed mine doing the exact same thing. SO I replaced the hose, but it didn't notice any improvements in my car.

I only have issues when it first starts up. It'll studder/hunt for the idle for about 15 secs. I was hoping this would have helped.

Good to hear it worked for you though.

Put gas in the car on the way home today, and the problem seems to have just about disappeared. I do so love this car.