Where should I start looking for vaccume leaks on my 2001 Passat 2.8 v6?

What is your question?

Car is hard to start when cold, and has a rough idle. I have replaced all spark plugs and wires, including the coil pack about 6 months ago. It's my daughters car and she mostly does quick trips. Not sure how the car reacts when it is warmed up and restarted that is something else I plan to check next.

How long has your 2001 Volkswagen Passat had this problem?

2 weeks