This is my third VW/Audi. We traded in our 2005 A4 for a 2008 A4. The engine after warm up sounds more like a diesel engine than a gas engine. Aude just serviced the car with 10,000 oil change. Service told my wife that all Audi a4's sound like this. Here is a video where you can hear car idle for about 45 sec then sound like diesel. Am I crazy or does or A4 sound a little off?