Normal boost/vacuum readings

[mallick@orion.crd.ge.com (John Mallick)]

I asked this about a year ago, but I figured I'd ask again...

Under "high vacuum" conditions (throttle closed, decelerating), what
sort of reading should I see on my boost guage.  The lowest reading I
see is 0.4 bar (it is 0.5 bar at idle).  I still think I have a vacuum
leak somewhere, although the car idles smoothly and seems to run fine.
However, I still can't hit a boost of over 1.5 bar no matter how hard
I try.  The car is a '91 200tq20v.

My friend's '88 5000tq will drop do 0.1 bar on deceleration.  I've
never seen numbers this low.  My suspicion is that one of those little
vacuum thingies has got a hole in the diaphragm somewhere, but before
I go sucking on hoses, I'd like to test the list-wisdom on this.

TIA,

John M.