Why can't I achieve the manufacturer's quoted mpg with stop-start?

The brochure for my car says combined fuel consumption is 67.3mpg with Start-Stop and about 62.0 without Start-Stop. I can only achieve 57.6mpg so, as you can imagine, I am struggling to better this and on a long run I still only do 57.9mpg, but the salesman says 57.6 is good. Any advice?

Asked on 2 March 2013 by WT, via email

Answered by Honest John
The ‘brochure’ mpg is the EC lab test figure, which is the only figure the manufacturer is legally allowed to publicise. It has nothing to do with real life. Over 8000 miles in 2008/2009 I averaged 55mpg in a Focus ECOnetic 1.6 110, not stop-start. What you are getting is about right. For the best information on what real drivers are getting on real roads see www.honestjohn.co.uk/realmpg
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