Raysanchez17

This has been happening several months and even my local audi dealer has no answers because it never happens when im there. Any time my 2004 A8L has been running for more than 30 minutes or so, the car wont start back up if I shut it off. It usually has to cool off around an hour before it starts. It doesnt have a power issue as all the electronics will work fine when not starting. Ill turn the ignition and just get one click follwed by a high pitch hum that lasts about 2 seconds. When if i try it over and over sometimes it will start but the EPC light will stay on. The car also will not pull codes when the light is on. Most times I will just have to let the car sit for a while and it will start fine. Am i just taking this to the wrong people? Or has anybody heard of a similar issue? Its just really frustrating not being able to make multiple stops on a trip because ill be stuck waiting for my car to start for long periods of time. Ideas?