Unround motor run

I have this problem.
My 3.6 L runs a little rough. ==References== 4 months was not moved I first changed the candles and cleaned the idle control, but it did not get much better. I did a little research there, because the car was at the Audi dealership due to the undisturbed engine run. The Lambda probe was then changed. The engine was installed in late September 03. It's a 91. Oil changes and all seals were also changed.
Can jemnad give me some tips on what it might be?
In October 03 also AU was made. The car is running at 800 revolutions.
He's the least "waking" he does in P position.

Thanks and greetings from Lüneburg.

Danny