Why has Shell's 'fuel saver' diesel increased my Chevrolet Cruze's consumption from 29.4mpg to 27.86mpg?

I have now run a Chevrolet Cruze diesel auto for over one year. Since Shell introduced "Fuel saver" diesel, my consumption has increased to 27.86 mpg average over the past 1,138 miles i.e. five tankfuls, whereas previously I was getting 29.4 mpg, which you considered to be poor.

I am perplexed by the DPF situation as I have never knowingly experienced a regeneration. I drive at least once a week from Edgware (a round trip of approximately 15 miles) to North Watford and most of my journeys are local or into central London. The yellow light came on once when I stopped overnight. Next morning the yellow light had gone out, never to reappear.

Asked on 3 April 2011 by GB, Edgware

Answered by Honest John
I tried Shell Fuelsaver diesel in a Citroen C4 2.0HDI 150 over a weekend and fuel economy improved from 51.1mpg over 430 miles to 52.2mpg over the next 317 miles. Not a lot, but still an improvement. Today, at an average speed of 70mpg on the A303 and A3 and a total average of 66mph, over 56 miles we averaged 46.5mpg in a Jaguar XJL 3.0V6 diesel, and subsequently 41mpg over 690 miles. Martin Gurdon averaged 42 in a standard wheelbase Jaguar XJ 3.0V6 diesel. So it's your type of journeys that are killing the economy rather than the car or the fuel.

I think you'd be better off using Shell V-Power or BP Ultimate diesel for the extra detergent effect that should be of benefit on your short runs from cold starts.
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