What would be the causes of lower vacuum? I get 16 most of the time than after a bit will go to 17 and hold for a while and go back to 16. It seems to be at 16 most of the time but will change instantly to 17 and then drop shortly after. This is at idle with the car warm and cold.

 

Vacuum is measured in mm Hg, not psi . RPM can change the amount of vacuum your car generates at idle. It's not uncommon for a cold engine to idle a bit lower until it warms up.

 

Your blower will affect the vacuum in the intake manifold. Vacuum is typically measure in "inches of mercury" ("Hg). Standard barometric pressure (14.7psia) is 29.92 "Hg.