Thanks for your reply, kewlynx. Interesting site - but it didn't indicate there was info on the vacuum system (a lot on electrical -but as a Bs in EE, I can manage my way in that area).

I noticed a fair number of "readers" on this subject, but not many pointers to help here.

I found this link via some googling: Vacuum 101 (or...Your Engine Sucks)- I think it may be useful for many here:
http://www.ih8mud.com/tech/vacuum.php

My first challenge is to get vacuum readings at all :-)

'91 LandCruiser