I currently have a 2015 Ford Focus 1.5l tdci ecoboost Zetec navigator. My MPG is usually 53-55MPG but recently every now and again it creeps up. The other day I went out and it jumped to 61MPG and now it’s 69MPG. It gradually goes up to 99MPG so I reset it and it stays ok for a few weeks and then starts to rise again. Also I think it’s using more fuel that it should be. I did 122miles on just over 1/4 tank doing average 60-75mph mixture of urban/country roads and motorway driving.  I think this is a bad fuel consumption? As my 1.8 petrol focus went to Cornwall from Rutland on 3/4 of a tank. Can anyone adivse me of the potential issues I’m having and how to correct them? And if I’m worrying about the fuel usage when it’s perectly normal amount?

Thanks

Chris 

Diesels use more fuel in cold weather. Only way to get accurate fuel consumption is to do fill the tank to the brim and check it like that. Fuel computer is not terribly accurate. By the way it seems pretty normal, my 1.5 diesel is much the same.

 

 

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as said above. Measuring it by topping right up at the start and then topping right up again to see exactly what you used is the only way. 'just over a quarter of a tank' is far too vague. I also find that the my gauge seems to go down faster nearer the bottom of the gauge so the last quarter equates to less miles than the first quarter (my car is fiesta not focus).

122 miles to quarter of a tank doesn't sound too bad for winter, that's about 500 miles to a tank.  I guess it's still a 53 litre tank in the Mk3 so somewhere around 50mpg is about as accurate as we can go without a brim test.  Even the brim test isn't perfect though, sometimes my Focus dumps a load of diesel on the forecourt floor when I pull the nozzle out...  

The trip computer obviously isn't right if it's just constantly going up until 99mpg.  Is it affecting the range reading as well?  Presumably it should tell you you'll get 1000+ miles from a tank lol?  Might be worth mentioning that to Ford in case it's a known fault, there might be a module update for it.

Are you sure this 99mpg you are seeing isn't the real time read out? Send us a picture of the screen.

Thank you for your replies guys. I will mention it to the garage when I take it in for service. DJ_Andy_M it’s definitely the average MPG, top right square on main dash readout. I’ll attach a pic of the current readings but as I said in my original post it creeps up to 99MPG over a period of time. Thanks again though guys I’m hoping it’s just a software update needed.