I have a 2006 A4 Quattro 2.0T and it has a slight hesitation with accelerating from a stop. It is a very quick hesitation but noticeable and irritating. A friend mentioned it may be in the airbox? any suggestions?

 

Dirty mass air flow meter or a vacuum leak would easily cause hesitation..

MAF can easily be cleaned.. The easiest way to find a vacuum leak is to start the car and let it idle.. Then spray started fluid on the intake likes that might be leaking.. If the engine idle gets faster: you've found your leak.. The rubber vacuum lines like to crack, and thee are a lot of rubber vac lines on the engine..