Hi all,

I have a 56plate C-max TDCI 2.0ghia.

Upon talking to a friend that has a fairly new c-max, he said that he has seen the miles before empty figure go up when he is driving.

When I look at mine regardless of what journey I do and driving style, it has never gone back up.

In fact when I fill up it usually says 450 miles before empty but then I usually only cover around 380-390ish.

I don't have a lead right foot either, so I am not sure where it is going wrong.

Also serviced recently too.

Any advice?

Hi Mark,

This is nothing to worry about at all.

Car 'computers' are rarely very accurate unless your buying up market.

The reason the miles to empty figure changes is simply because the car estimates the figure on real time data, so if you fill the car with lead and drive up a hill at full throttle the car thinks OUCH only 100 miles left, when you coast down the other side of the hill it thinks, 400 miles left and adjusts your 'miles to empty' reading accordingly.

My Focus TDCi does it, reading is fairly steady but never accurate.

The computer in my Spanking new mercedes is absolutely spot on though, so basically I think we get what we pay for.

Do you have cruise? if so use it wherever possible, freewheel down hills (engine on), anticipate junctions and you will really knock up your mpg and miles to empty figure.

Does all that make sense??

Trip computers base the miles remaining on your driving for the last few miles (ie not since you last reset) so can vary. Typically this will only be downward but it's not unusual to see it go back up as Mark has said. Mine typically goes down on my drive home from work (uphill, trafficy, etc so it's never going to go up on that journey!) but quite often goes up while parked at home as my driveway is on a slope and tricks the computer into thinking there's more in the tank. Soons drops back down again once I drive off!

Another tip for saving a load of fuel is to keep your speed at or under 60mph on m/ways and dual carriageways.