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Coast to Coast

The article by Kara Gammell in the Money Supplement in a recent Sunday Telegraph stated towards the end:- "But don't think that freewheeling down a hill will save you petrol. It won't. Not only is coasting dangerous, but due to changes in vehicle fuel systems, it will not save you any money on petrol.” Whilst accepting that freewheeling could be dangerous, I was always under the impression that it could reduce petrol consumption by anything up to 10%. What is your view on freewheeling to reduce petrol consumption?

Asked on 9 October 2011 by EJ, Frodsham

Answered by Honest John
It doesn't. Because modern fuel systems supply no fuel to the engine when you lift your foot off the accelerator pedal. The engine is turned by the car's wheels and its drivetrain. If you put it out of gear and coast down the hill with the engine idling, the engine will use a small amount of fuel in order to idle.
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