I have a 2.0 TDi 170 that I've had from new (Sep 06), and ever since we've had it there have been problems starting in cold weather. This ranges from a brief bit of roughness, through to total failure to start (crank all you like, it might cough but it never catches).
TBH it's got beyond a joke - I've had Roadside out to it 4 times, it's currently in the dealer for the 5th time (and this time they've had it 11 weeks so far...).
Things I've noticed are:
1. It's worse if the fuel tank is less than half full
2. It's worse if the car's on a rearward facing slope
3. Even when it does start "normally", it's not clean for the first few seconds. There's no overfuelling, the revs don't rise over 1000 at all, and it feels like it's running one cylinder short. This is just for a few seconds, but...
Anyhow, the dealer has escalated it to Audi UK, they've passed it to Germany, and they've got a couple of other cars in to try that are both showing similar symptoms (although those haven't yet gone as far as totally failing to start). Things they've changed on mine that haven't made a blind bit of difference:
1. Coolant sensor
2. Engine speed sensor
3. ECU (yes, changed the whole thing, not just a reprogram)
And a couple of other interesting points I've heard (dunno about reliability, but):
1. A4 170 used to have similar problems, was fixed in software, but no equivalent fix for the A3
2. VW have this problem with the Golf 170, possibly more common?
I'd love to know if I am the only one experiencing this issue, especially given the previous couple of anecdotal points.
So ... anyone else?