I agree with IsaacCarlson. You really should get a mpg gauge to learn the idiosyncrasies of your car, though.
I noticed that in my car I tend to get worse numbers when I do straight P&G. Once I am up to speed I will apply the lightest pressure to the pedal to maintain speed. The instant consumption gauge shows between 48 to 99 mpg then. If I pulse and glide, that time spent accelerating at about 22mpg ruins the >99mpg I get on the glide.
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