I've heard that 17 is right on the money for vacuum, but honestly the Autometer guage doesn't give a really good reading in my opinion. This is coming from some who always buys them however. LOL......
I run 18-19 when the car is warmed up, 16-17 while cold just for reference.

 

I have I think 6 vac. lines... still 10lbs. I might replace the PCV valve for the S&G of it to see if it helps. I'm going to also tap and bolt shut the unused vac tips I'm not using. Besides that is kinda hard not to find a bad line.

 

Anyone else have any input?

 

if it's low idle and it's rough that most likely = KABOOM.

 

My '81 RX-7 held 14 lbs of vacuum before the engine let go at 190,000 miles. If you're using a gauge, make sure you're getting the vacuum from the right place.

The hose that goes to the Blow off valve will read the correct vacuum. When the throttle is open, there's "less vacuum" and when it's closed you should have "more vacuum"... or read more/less vacuum.

Vacuum gauge is a fun/useful gauge to have in your car if you don't have one already. You can get a standalone vacuum gauge.