Audi Repair: Starting problems, crank sensor, audi a4

Question
Hey!
I have a starting problem with my car.  Its a 2000 Audi a4 1.8 quattro.
Some times it just wont start up for me.  For instance i have been driving it for the last few weeeks and it has been great, but just yesterday it didnt start.  If i leave it for awhile, or over night is usually always starts up.  It cranks but just dosent fire.  Its not my battery or my starter i have checked both more than once.  I have some reason to think it may be my crank sensor?? or an electrical issue?
Any help would be great.

Thanks alot
Steve

Answer
There can be many reasons for a no-start; however they do not normally cure themselves unless it is simple flooding.  I need some more information to see if there is a problem with the car, first thing I would do is get the codes read out and see if there is a code in the computer.  Let me know,  Jan