I need a vacuum diagram for a 2004 XJ8, I get a Lean Bank 1 and Bank 2 reading. I was told it normally means a vacuum leak when you get two readings such as this, and I want to check it out before it goes to the mechanic.

Which engine, 4.2L N/A or 4.2 S/C?

The engine is an N/A, sorry I wasn't clear about that important item.

Check the service manual. In the Stickies