Car is suffering the BKD lumpy idle syndrome.
So far established DMF on way out as has the odd chatter now and again, but not replaced it yet.
However, also had timing belt done at Audi a couple of months back and felt much lumpier when retuned. It went back to be checked out and was returned with the cursory "they all do that sir".
For the last week or so, I've started getting a puff of smoke on cold startup that dies not look good. After initial start, no smoke at all. No new noises, no loss in performance. Also, no smoke when started warm, or when started after being left at work all day, only smokes when left overnight (c.13hrs).
Could it be just that the fuel timing is slightly out and Audi fobbed me off, or is it another common fault I have to look forward to?
How can I go about diagnosing the fault?