I have an 2003 A4 1.8 turbo with95,000 milesthat has been giving me trouble for a few years with the ignition. When the dealer has it they never can find a problem. When I start the car it often immediatly stalls. It happens when the car is cold, first thing in the morning, and when I have been driving all day. Sometimes the car starts on the first try and on other times it has taken up to about ten attempts to start the car . It seems to help if I turn off the radio and ac before I turn the car off and get out. If it does stall it seems to helpif I pull the key out of the igniton before I try again. The dealer replaced my key and the security id unit about a year ago, but that did not fix theproblem it did seem to decrease the frequency of the problem.I live in Phoenix, AZ and the problem does seem to getworse in the summer months. The most frustrating partis that it seems so random. The car will be fine for several days or the first half of the day and then it stalls several times every timeI return to my car.If anyone has any suggestions please let me know. Thanks

 

I'm having ignition trouble too, 97 B5 A4, the story I keep gettingis that ignition problems are common on A4s, and the source is the"Ignition ControlUnit". Small, flat sensor on top of the air box. Seems to be a tempermental little thing. Not sure if this helps, but that was my problem. good luck!

 

This could be a fuel problem, vapor lock or fuel starvation.