I did a sum the other day (cant remember what it was) and calculated that my car did 26mpg.

But i did the same today and got the answer my car did 18mpg on the fuel i put in. :S

Basically ,the fuel light always comes on on the Friday night just as i get back from work (bout a mile away), last saturday, i put £35 of fuel in in the morning @ £1.28 a litre (normal unleaded) and got 170 miles out of it.

But this saturday i put in £20, also @ £1.28 a litre, and got 76 miles out of it?

Both weekends consisted of 60 - 70mph on dual carriageway A road driving, sat at around 2500 - 3000 rpm for around 40 miles, about 25 -30 miles of town driving, the weekend before when i did more miles was just more A road at similar speeds.

Car is 2000 reg, Mondeo 2.0 16v Zetec blacktop, standard other than drilled airbox.

Just seems this morning, (the light had come on on the way home from work last night as usual) i put in £20 @ like i said £1.28 a litre. got to my mums (20 mile on A roads) drove around town visited a couple of friend, then drove the 20 miles back tonight on A roads, 76 miles later, i got back home,and light came on halfway home from my mums aswell.

Does this sound right?seems to be costin me a feckin fortune in fuel, putting a fiver in it seems pointless aswell, the light can come on, be on for literally a couple of miles, ill stick a fiver in, drive the 3 mile home, drive 4 mile to work, 4 mile back, and the lights on again :S