Can someone explain how a vacuum gauge works and what the numbers mean. I am wanting to purchase a vacuum gauge for my car but need to know what numbers to maintain and which numbers to stay away from. Right now I do 50%/50% driving in town and freeway/highways. I joined fuel mileage web site and recorded all my mileage and right now I get 28.5 mpg at 0.11 cents per mile. Thank you for your time.
1. To tell you when you are stepping on the gas pedal too hard and therefore driving too fast/hard. You would try to keep your vacuum high. In my opinion you could just use your foot and your speedometer for this, but some people find it to be a useful addition.
2. For people like me who use a heavy-throttle technique to reduce pumping losses and avoid wasting energy creating a vacuum, it can probably tell you when additional throttle won't make a difference. In this case, you would try to keep your vacuum low.