What's the most fuel efficient car

[KJ_Lesnick]

Hobbes

A series hybrid does have a continuous connection between the ICE and driven wheels, unless it's equipped with 'sailing mode' which declutches automatically when you release the throttle. I suspect the only hybrid that qualifies under your rules is the first-generation Honda Insight, which is less efficient than the Lupo 3L.

That's basically the issue -- no sailing mode...

[KJ_Lesnick]

Bump

[Hobbes]

In the US, the Mitsubishi Mirage is the most economical non-hybrid according to this list: http://www.fueleconomy.gov/feg/PowerSearch.do?action=Cars&path=1&year1=2013&year2=2015&mclass=Hatchbacks&srchtyp=newMarket&pageno=3&sortBy=Comb&tabView=0&rowLimit=10
But there aren't any diesels in that list, and as already said, a small diesel is going to give the best results.

I haven't found a better list for European cars than the one I gave on the last page.

[McColm]

If you lived where the sunshines 18 hours a day then solar panels driving an electric engine. Dodgem cars. Depending on the grid.
I managed to get 65 miles out of a 1.6L Ford Focus 2009 with every warning light showing on the dashboard and fuel tank showing empty.
The C1 1300cc is impressive as four blokes drove one from Blackbushe Aerodrome to Stirling Castle Scotland and didn't need to refuel it.

[Go4fun]

I had THE most fuel efficent car as a young whipersnapper.
A little red fire trucker fueled by Sugar Frosted Sugar Bombs and powered by pedals.

[JayBee]

At the moment I am driving a 2.2litre Honda Civic diesel and I get about 55-60 in my normal driving (and it will out accelerate a Golf GTI  ). Long runs it is even better, and if SWMBO is doing the driving then it is even better still.

Jim

[PR19_Kit]

I drive a 2003 1.8 litre Vauxhall Zafira Dualfuel, which runs on LPG most of time. It gets 30 mpg, but as the fuel costs less than half the price of diesel, that's about 65 mpg in money terms. 

AND it doesn't pump out soot & smoke particles and its oxides of nitrogen output is zero. Please don't tell me diesels don't pump out soot and smike, I drive behind them and they certainly do, even new ones............