I have a 2001 A6 2.8 and after it warms up if you turn it off then try to turn it back on a minute later it just cranks like it wants to start but only does after it cools down for about 5-10 minute. Just started doing this after I replaced the valve cover gasket and seals. Could it have anything to do with the valve cover gasket?

 

It was the crankshaft position sensor.

 

I would have guessed temp sensor...but normally that activated CEL...thats what mine was...another future reference option