I never had a Turbo Charger before. In a general sense understand what the Boost gauge is telling how much it is pushing into the engine but but wonder what its readings are good for? I'll bet when it is reading above Zero and "boosting" it is making power and sucking a lot more gas. So if I don't need a lot of power driving around town should I use the gauge to try to get the best mileage by keeping the boost below zero? If it goes negative is it a drag on the engine? or just not doing anything?

I should probably learn how to spell Gauge or at least settle one a single misspelling...

 

It's not your spelling, it's the 'firing order' of your keyboard that fires the 'u' character out of order with the 'a' key. Mine does the same thing.

If you believe THAT, there's no sense in me trying to explain "BOOST". But basically the reading is good indicator of general turbo health. Other than that, power is power and the more Ft Lbs generated = more fuel. A vacuum gauge, for economy, best to keep it as HIGH as possible. For Boost - opposite.

 

Boost gauges are good for monitoring wastegate performance, or general tune reliability. A steady, consistent reading is a good thing. As far as vacuum goes, typically, the more you stay out of boost the better gas mileage you get. No, there is no additional strain on the engine, just means that the manifold pressure is a vacuum instead of being pressurized (like a naturally aspirated car). What year truck do you have. This is the 2004-2008 section, so responses may be limited.