My TDi 90 idles at a steady 1000rpm too, so that seems to be the norm.
Recently though, my A2 has developed a stutter or misfire at between 1800 and 2200 rpm, as though the engine is about to splutter and die.
VAG-COM shows no faults, so I assume that it is the MAF which is on its way out. Another one for Smith Knight Fay to add to the 'to-do' list!