Yorkshire mick

I think this is something biting me in the backside abit now. I have the 245bhp quattro 3.0l love it really do and love the engine. Personally I'll be getting the BiTDI next but in meantime I am starting to get rough idle at cold which I feel maybe a dmf issue. Just started to look into it now hence I'm here. Drives amazing had it 2 years I do high milage. I do king trips but also short and that's the issue. It's my first diesel and auto and I really love it. I've had no issues in the 2 years and I'm now at 115k just had service but the idle still feels rough. It does not stall but does vibrate enough to move cat abit. As I say drives fine and no dash lights or anything shown up and simple check. Hoping might get a better idea.