Fuel supply system, checking for leaks

WARNING: This page does not describe the selected car, but rather 6 other vehicles, including the 2009 Audi S4, 2008 Audi S4, 2007 Audi S4, 2006 Audi S4, and 2005 Audi S4. However, it is still accessible from the selected car via links, so may be relevant.

Let engine run a few minutes at average RPM.
Switch off ignition.
Check entire fuel supply system for leaks.
If there are leaks in spite of correct tightening torque, the corresponding component must be replaced.