ive heard that new engines are a little tighter until run in and therefore less fuel efficient and that after around 3000 miles average mpg gos up . is there any truth in this? the car in question is a 2011 focus sport 1.6 tdci

I have also read the same thing.

It's not just fuel efficiency that improves - power and response also improves as the engine loosens up.

we found with our 1.6 tdci 2010 focus zetec that after its first service it really improved in every area :)

just out of curiosity what average mpg are you getting from your 1.6 tdci?

it has 3 diffent drivers me, my dad and my mum , me and dad can easily achive 57-60 mpg on a tank , but my mum can only do about 40 mpg wen she uses for town but she drives it like a petrol i.e changes gear at about 3500 rpm , me and dad both change gear at about 1800-2000 rpm, but if i take it for a long drive it will do 70-74 mpg. :)

3000 miles is the universal testing benchmark. When the car is manufactured, it is run for 3000 miles, before it is then handed over to independant testers who then do a rolling road test to identify the urban / extra urban fuel consumption rates. 3000 miles is classed as sufficient run time for all parts to bed in and settle down, as they need to be bedded in as everything is rough and jaggered from being made in the factory, after 3000 miles resistance is reduced as due to "wear and tear" the engine block, cyclinders, belts and pulleys have all been subject to use, and any imperfections / rough parts have been worn down to a smooth surface.

So yes there is truth in it. if anyone is interested in the subject of how they work out the fuel consumption, then I will dig around and find the article and post a link, but yes, there is truth...