Mercury sable 2000 DOHC and possible vac leak and?

I have a Mercury Sable 2000 V6 DOHC and it is idling erratically and even stalled at red light. I notice a slight hissing sound coming what I think is the intake manifold. Could it be the gasket? Engine light on and Codes read system too lean bank one and bank two. I would really like to check vac hoses on this but I don't quite understand the layout that is printed on car itself. Thanks in advance for your help.