When doing a vacuum pressure test, should your lines hold the vacuum after the engine is shut off? If you just put the pressure gauge in line with any of the vacuum lines it'll check the whole system right? There isn't a certain place you need to put it? I checked my '94 runner last night and it was reading about 17, but the vacuum dropped as soon as I shut the engine off. I checked my wife's Accord just for fun and hers read about 17, and up to 20 when rev'd, but hers held the vacuum even after the engine was shut off.

 

Vacuum will drop to zero when the engine is off, no suction on the intake = no vacuum. Maybe the line you checked on the Accord had a check valve to keep the vacuum. I know the ADD system on Runners has this. And yes, the vacuum will be the same on all lines.