I've been having this problem for almost 6 months now. The car stars up fine, idles, drives, runs great! Very randomly it will just shut off or stall with no warning, just boom, stalled. The car will then start right back up, and drive fine.
Now the weird thing is that in warm weather the problem occurs more frequently at lights, stop signs, and stop and go traffic. There will be days that I will start the car cold and drive to work (20min highway) and the car will run perfect. Then there's days that it stalls as soon as it idles for 1 minute or so cold. The car throws NO codes other than engine output speed, probably due to it stalling, but this is a pending code and does not force the engine light on.
I have replaced all spark plugs, fuel filter, cleaned the throttle body, replaced the battery. I brought my car to my local mechanic and he said they couldn't find the problem because it's restarting fine and there are no codes. HELP!
Random stalling in cold weather and excessive stalling I. Warm weather while in gear or in park, only at near idle or idle. Starts right back up. Occasionally the car will surge in park and then sputter out. Thanks. Nick.

 

Codes as in generic code reader or VCDS ?

 

It's a actron 9589 plus scanner. Pulls no codes.

 

That's a generic reader and is not able to pull detailed information.
I would either get a VCDS, find an independent mechanic with one, or see if you can find someone to scan the vehicle.

There are many more pieces of information the Ross-Tech tool can retrieve from an Audi.
Just 2 hours of Audi dealership diagnostics would pay for VCDS.
Lots of other handy things it is capable of too.

Ross-Tech Store: VCDS License with HEX-USB+CAN (all VAG 1995 to current model year)

Auto Scan: Ross-Tech: VCDS Tour: Auto-Scan
Tour: Ross-Tech: VCDS Tour
Wiki for D2 Audi A8/S8 (4D) - Ross-Tech Wiki

If it were a D3 my guess would be crank position sensor or vacuum leak, but I'm not terribly familiar with the D2.
Perhaps someone will be able to give additional ideas.

 

Thanks for the tip. I replaced the CPS and checked all vaccum lines.