I have an 2003 S4 Avant and have been experiencing intermittent start up problems since last winter. Basically, when you turn the key there is no turn over or anything but all the dash lights etc read as ok. Then after maybe 10 sometimes 20 minutes of trying the ignition the engine suddenly kicks in as normal! Once the car has started it will be fine all day (even if left for 8 hours) until the next morning. I have seen similar threads but nobody seems to have a definitive answer. Like I say this is an intermittent problem so sometimes it is fine, but I have now resorted to trying the car an hour before I go to work, just so it starts on time!
Can anyone help!!