Not an Audi (obviously) but seems to be a lot of good knowledge on here so thought it's worth a shot.
We've got a MK3 diesel golf and in the last month or so been having trouble starting it. Really have to give it some beans to get it going, otherwise it stutters and cuts out. Once it gets going its really smooth and reasonably quiet. It's only really used for short journeys on a day to day basis with longer journeys at 50-60mph over the weekends, about an hour long 5 or 6 times.
We treated a tank of fuel to some fuel cleaner, but no change on the following tanks, still doesn't like starting from cold. It was a cheap cleaner so plan to try a better product, redex or slick50 maybe. We've had the glow plugs checked and they were fine. They said to turn the key and when the coil goes out turn it off and on again a couple of times, just to let them really heat up before trying to start, but no change.
With how well it does run, fingers crossed it's nothing serious. Here's hoping. I'm going to take it for a good blast up the motorway at the weekend to see how it goes.
So, is there anything else I should be looking at?