Hey, I've owned my focus for over a year now, and just recently I've noticed the economy of it has dropped by 12-15mpg. I am 19 years old so I know I don't ALWAYS drive the most responsibly, but when I was driving 50 miles on the motorway a day for work then coming out of an evening a giving it a bit of a rag about I was getting 65-68mpg average. Now I havnt been going out as often, and been driving to work very sensibly doing 55mph I am only getting 50-55mpg. And a full tank used to get me near 700 miles, and now only a full tank gets me slightly over 500 miles.

Has anyone else had a similar issue to this? And if so what did they do to help get it back up? Any help would be much appreciated. 

(I've noticed thus over the past 2 months or so)

Hi

In car mpg readouts aren't very acurate. Try working it out manually.

Fill to first click then run till a certain point then fill again take the number or litres as below.

Litres to gallons / 4.546

miles divided by the number of gallons.

My 2017 does around 56mpg but thinks it is does 62+ mpg.

Paul

cold weather and winter time lowers the mpg as your car has to work harder to warm up. 

55mph isn't necessarily better for mpg than 65/70mph.  It's an outdated idea from 20th century cars.  Aerodynamics have come a long way and top gear is generally designed for UK motorway speeds nowadays.

The biggest difference here sounds like your mileage though...if you're only doing short journeys at slow speeds the engine won't warm up so quickly, or perhaps even be at operating temp time you reach your destination.  It'll be much happier doing 50 miles at 70mph.  There is no replacement for mileage unfortunately, but you can take solace in the fact that your consumables like tyres aren't being worn out so quickly, offsetting some of the extra fuel cost.

Another thing if you are doing short journeys, the car could be in a constant attempt to regen the DPF which significantly lowers fuel economy.

5 hours ago, TomsFocus said:

55mph isn't necessarily better for mpg than 65/70mph

I agree with "isn't necessarily" ..... but in reality, 55 IS generally better for fuel economy than 65/70  (You should be in top gear at both speeds).

You can test this by trying two identical journeys (say 30 miles on a clear motorway) at different speeds and use the onboard computer for comparison purposes i.e. the real mpg numbers may not be accurate, but the principle should be demonstrated one way or the other.

I get best economy out my Mondeo diesel  at precisely 48mph in 6th just over 1100 rpm. Easily achieve 75mpg on trip computer to work and back. 😀😀

2 hours ago, alanfp said:

I agree with "isn't necessarily" ..... but in reality, 55 IS generally better for fuel economy than 65/70  (You should be in top gear at both speeds).

You can test this by trying two identical journeys (say 30 miles on a clear motorway) at different speeds and use the onboard computer for comparison purposes i.e. the real mpg numbers may not be accurate, but the principle should be demonstrated one way or the other.

I have compared it in a few different cars and found the difference to be negligible.  I used to be super anal about mpg, using the brim method every time and recording it all in spreadsheets...

 

8 minutes ago, TomsFocus said:

I have compared it in a few different cars and found the difference to be negligible.  I used to be super anal about mpg, using the brim method every time and recording it all in spreadsheets...

 

That's one thing I've  never done. No mpg spreadsheets for me. But I do task my self with trying to beat my drive to work trip computer economy figures each day . Best is 82mpg . Can't seem to beat that whatever speed , time of day, weather etc. Wind tonight was against me so that dropped mpg by a few miles. 

Maybe the amber warning in my area for wind will help me tommorow to work.  😂😂😂

5 minutes ago, iantt said:

Maybe the amber warning in my area for wind will help me tommorow to work.  

Can you rig up a sail tonight?

28 minutes ago, TomsFocus said:

Can you rig up a sail tonight?

What a good idea!! 

 Rather depends on which direction you're travelling. Could be a record 100 mpg tomorrow, or a record 20 mpg!

24 minutes ago, alanfp said:

 Rather depends on which direction you're travelling. Could be a record 100 mpg tomorrow, or a record 20 mpg!

Well, it was blowing against me tonight. Forecast tommorow is the same direction wind , so to work should push me along nicely, so we shall see. 

Seriously a tail wind does have an effect. I once had to drive for 40 miles along a very exposed road ( The Devils Beeftub road) with a strong tail wind behind me and my car ran a lot hotter than the usual halfway point. Presumably there was not as much cooling air coming through the grill.

I never noticed the Fuel consumption changing because it was part of a lot longer journey.

On 2/16/2022 at 5:34 PM, Haydn gillman said:

Hey, I've owned my focus for over a year now, and just recently I've noticed the economy of it has dropped by 12-15mpg. I am 19 years old so I know I don't ALWAYS drive the most responsibly, but when I was driving 50 miles on the motorway a day for work then coming out of an evening a giving it a bit of a rag about I was getting 65-68mpg average. Now I havnt been going out as often, and been driving to work very sensibly doing 55mph I am only getting 50-55mpg. And a full tank used to get me near 700 miles, and now only a full tank gets me slightly over 500 miles.

Has anyone else had a similar issue to this? And if so what did they do to help get it back up? Any help would be much appreciated. 

(I've noticed thus over the past 2 months or so)

I've noticed the fuel makes a huge difference. Filling up at supermarket pump always gives me bad results in terms of fuel economy, i end up paying more than big brands like esso or bp...

Could there be a difference due to the winter blend of diesel if that’s still a thing?