A6 Cutting out at low speed

[DurbanDriver]

Hi everyone. I am getting desperately frustrated. I have an 1997 A6 2.6 Avant Auto.
Almost everytime I brake to stop at stop lights or to take a slow corner, the car cuts out. It starts again immediately if I slip it into neutral and turn the key. The local agents have been unable to pinpoint the problem. It has been back various times and so far they have replaced - the battery, plugs, plug leads, knock sensors - in addition to the normal servicing.
I have heard that the throttle body can get dirty and I have asked them to clean it specifically, and they say they have, but the problem has never gone away. Of course it never does it on a test drive.
My home town is at 600m and the dealer is at sea level. This is the only thing I can think of but the dealer says that has nothing to do with it. It definitely happens way more often in my town than at sea level.
My wife refuses to drive the car, because it is really unsafe when it cuts out in a corner - you loose power steering and braking. I am really not popular for buying this otherwise really comfortable and practical car.
Any suggestions would be really appreciated.

[HellBent]

Does the car misfire at low speeds or any other problems you're having?

[DurbanDriver]

Originally Posted by HellBent

Does the car misfire at low speeds or any other problems you're having?

The car pulls well at low speed. Lacks power at high revs almost as if the timing is not advancing enough. Which is why they replaced the knock sensors, but it hasn't helped.
When it does idle it seems to idle fine, not rough.

[flavio]

Hey guys, my 97 A6 Quattro (116K Mi) started exactly with the same problem yesterday: "everytime I brake to stop at stop lights or to take a slow corner, the car cuts out. It starts again immediately if I slip it into neutral and turn the key".
In addition to that its AT transmission also started shifting hard, almost no clutching.
Any suggestions would be greatly appreciated.