ICE cars are much less efficient when cold, but we know this and ignore it or just complain that the fuel consumption isn't as good as it was....!
To be honest, I haven't noticed a drop in efficiency in my Corsa. It tends to get about 360miles (about 43mpg) before the petrol warning light comes on, time after time. I've tried driving it as economically as possible, or thrashing it down the motorway and I get a maximum of +/- 10miles difference on a tank full.
