buggered MAF?

[jonesltd]

Filled right to top and done 51.7 miles amd seems to have used some fuel to the next bold line? Was it because of cold weather or need to replace maf? Currently running 42.7 average with heating on and not a/c or dual

[legg360]

I wish I got 42mpg, I don't drive hard and if I do it's never for any long amount of time, most of my driving is on the motorway and I sit at 60, little 10 mile trip today on the motorway and was ave about 38, my total ave for a tank from fully full to nearly empty was 315miles and ave about 28mpg with a good mix of town, motorway and rural driving

[Snoopy]

Deisel winter fuel is a different mix to summer deisel fuel. I see large differences in the mpg between the two. Last year my PD TDI dropped by near 10mpg using the winter deisel 

[legg360]

Is that the same for petrol tho, I have noticed I my exhaust pipe tips sut up very quickly and even when the engine is warm you can see the smoke coming out the exhaust pipe, it don't seemed to be a different colour just normal grey smoke could it be running rich?