Vacuum leak 1996 4.6 Northstar

What should the vacuum reading be while the engine is idling,using a vacuum gage? Also @1000,2000,3000 RPM with And without load?

I have found this to be a great guide to using the gauge:

Thank’s for your reply but,Can’t get in site. It produced a program error. What else?

It would be helpful for you to find a basic guide (there is one in all repair manuals).

Normal vacuum should be between 16 and 22 lb with a steady needle. It will also vary with elevation (about 1 lb lower per 1000 ft). If you rev slowly and steadily the vacuum should actually not change a whole lot but the faster and more you open the throttle plate the more it drops the vacuum, though it should shot straight back up when the throttle closes.

The link I posted is good b/c it has animated diagrams. But there are plenty of basic guides out there.

Are you just trying to chase down a vacuum leak?