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Vehicle MPG computers
Why are MPG computers on cars so inaccurate? I have had a Focus Econetic which was up to 6 MPG out and now have a Mercedes C200 Blue Efficiency which is also up to 6 MPG out, although unlike the Focus at least the Mercedes does the stated manufacturers MPG figures. The Focus stated uo to 80 MPG but was more like 57 MPG, I wonder how many unsuspecting motorists are being duped by these faulty readings, I always fill the tank to the brim and use a calculator in the old fashioned way.
Asked on 25 May 2013 by gajhc
Answered by
Honest John
To make you feel good. I had a Focus Econetic. Started at about 63mpg, but fell to 55mpg (calculated) over 8,000 miles. The BMW 320dED I ran once showed 82 over 250 miles, but the calculated average over 7000 miles was 63mpg (which is still fantastic). www.honestjohn.co.uk is a mix of dash metre and properly calculated mpgs, which helps to make it a true average of an average of an average.
Real MPG enables you to register the fuel economy you are actually getting against your make and model of car, its engine and type of transmission.
Every time you enter an average consumption figure against your car, the overall average automatically adjusts to reflect it.
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