[SeaSlugs]

Originally Posted by Y-Blockhead

I have a Stewart Warner Motor Minder, dial is color coded and pretty self explanatory as long as the needle is steady. If the needle is not steady a vacuum gauge can show many other issues.

that chart is the best ive found across the web. holds true for any engine any year (altho im not sure what a super modern car with variable valve timing and all sorts of fun trickery would show)

print it off on a full sheet of paper and keep it in your toolbox!