http://www.therangerstation.com/Maga...acuumLeaks.htm
Take a look at this web page. It has about the same vacuum diagnostic images that Dieselholic posted, except the images are animated.
Please take a close look at that first section on finding vacuum leaks.
They offer several methods for checking for vacuum leaks. Of those, the preferred method for me is spraying carb cleaner.
It should be noted that unless your eye balls have been calibrated specifically for checking for vacuum leaks, your results from just looking will be generally very unreliable.
They say normal vacuum should be 17-21 and are showing 20 in.Hg.
Your signature says Redmond, WA and Google says that is 43 ft above sea level.
If any engine is going to get 20 in., it is going to be that close to Sea Level.