I have a 2000 s4 and so a little while back my car all of the sudden wouldnt start but the battery alternator and starter are all fine and up to par it will crank but not turnover. Question is though what could it be? It does die if I idle it and at a stop light it will die as well. Ocasionally I cannot start it after running it for a little while. and also i changed my camshaft sensor on the left side if your looking from the front bumper. I need to fix it asap but cannot figure it out at all and its really annoying when it doesnt start or when it just dies.
thanks

 

ignition solenoid? idk this is the A4 forum so most of us aren't too familiar with the S4 and how it's setup

 

does it only happen when the car is warmed up? cause i had a slightly similar problem with an a6 and it was the crankshaft position sensor. It would overheat and then would allow the car to start until it cooled. just an idea