I have been driving as econimacal as i can lately to see what range i can get from my 2003 TDCi 115. My light came on at 525 miles, so i will probably get 550 out of it. I filled the tank to the neck, but do the manufactures take a full tank as when it hits the full mark on the gauge or if you fill it till no more will go in?

I used to get 470 miles approx when i used to drive it harder, but i cover longer distances now and drive smoother. So what would my mpg be now?

Hopefully you'll still have the receipt. It should detail how many litres you put in. Divide this by 4.54 to get the amount of gallons you out in.

Then divide 525 by the gallons put in to work out your mpg.

if its motorway miles you do, at a steady 70ish ours can return 68 to the gallon. 1.8 tdci 115, a cat back s/s. has a cold air feed induction kit, a uprated front mount and a re-map.....