How do you drive it? The Back box and K&N make a great sound when pushed but obviously MPG will suffer. So drive it carefully but enjoy ablat once in a while on an empty open road.
1, Is the thermostat correctly opening at the right temperature.
2, Are the wheel bearings in good condition
3, Tyre pressure - this can have a big effect on fuel economy taking upto 6 mpg if the pressure is wrong.
4, has someone attached a caravan or trailer to the back without you noticing.
5, Are the local kids syphoning off the Fuel overnight.
