Mileage

[Daisybell]

I have owned my 59 plate focus for a month now. I just don't get what is going on with the mileage. The first time I filled up it said 407 miles. The second time was down to 380 the lat full tank only 360 any ideas what has caused the drop? I'm probably getting the mileage the car suggests I just wanted to know why the estimated mileage has dropped so much.

Any suggestions how to bring it back up or was the 407 a fluke greatly appreciated.

Thanks I'm new to the forum.

[Preee]

I gues the only real way to test would be to put the exact ammount same fuel in a few times and see what it reads , and it would depend on how much was left in the tank when filing.

[btmaldon]

Are you doing a lot of short runs? Only mine normally shows between 440 and 460.

[james132]

Go back to old school maths and work out your mpg, the car reading may be out abit.

[Daisybell]

Thanks for the replies. I guess I do a lot of short 5-6 mile trips. Does the fuel quality make a difference? I was considering using redex. Will it make a difference?

[fernsie]

I'm getting really annoyed at my estimated fuel at the moment ... it's almost always telling me 0 miles after i've completed about 500

If I fill it up at 0 miles, I can only get about 43ltrs in it ... means there is still about 10ltrs in the tank!!

- Still got about 100miles worth left in the tank!!

I estimated one day that if I was brave enough to run the car till it ran out, I could get about 620miles out of it based on how many miles I had done and how much fuel I put in ... don't think i'll be trying it any time soon, but why tell me i'm empty at 500miles!!!!

[TDCiST]

Yes fuel quality will.

I've used various additives, only one ive found ever work is Millers Sport Eco-Max for diesels... Gave me about an extra 1-3mpg... even when thrashing it!! Short journeys are a killer for economy, especially in this cold weather!

Is it diesel or petrol??

[Pitmonster]

I always fill my car to the very top, and then note the litres off the pump against the miles on my trip meter. A simple calculation and you can easily work out your true & accurate fuel consumption. You don't need to run the tank empty, but you do need to fill to the very top each time, and zero your trip meter each time. It's always good to compare to your mpg reading on the dashboard too.

If you have an iPhone or iPod touch there's a free App called Road Trip Lite that works it all out for you. I expect there are similar apps for Android too.

The figure on your trip computer is just an estimate, and like any estimate it uses an assumed mpg figure - which may differ from the real figure that you go on to achieve. I've had my Mk2 1.8 TDCi for 6 weeks now, and when I filled the tank on the day I bought it the trip computer gave me an estimated range of 360 miles (I actually did 500). The second fill said an estimated range of 420, and I did 530. The third fill said 480, but I've yet to fill it up a third time.

I can only assume that the ECU records recent mpg data and uses that as the basis for the calculation. If the owner before me was heavy footed, or all his driving was stop-start city stuff with no motorway cruising, his mpg would be lower than mine and therefore the estimate given by the trip computer would be lower than what I actually achieve. But the longer I own the car, the more that estimate is based on my own driving style and journey type, and the more accurate that estimate will become.

As you have only recently bought your car, I expect it's the same situation, and the longer you own it the more accurate the estimated range wil be.