i have a 2000 A6 2.7T and lately the car has not been starting, it just turns over usually i just wait and try again and again and it will eventually start but sometimes it takes up to an hour before the engine will start. Then once i get it going it will stall out while im driving and the engine will die sometime it will start back up right away and sometimes will just turnover. i always put 93 octane in and im sure its not the battery could it be dirty or bad injectors? any help would greatly appreciated

 

Fuel spark air. Thats all you need for the engine to start. Check for faults in the ecm. My top too guesses in this situation would be fuel pump or engine speed sensor. Could also be something with the throttle body or ignition switch. You cant really rule out the ecm either.

 

I have a 2000 2.7 that did the same thing. It eventually wouldn't start at all. The ECM was dead.It was covered by AUDI for 8yr/80,000 miles, so I got it fixed for free. Good Luck.