Hey there,

Bought my first car on Monday. 09reg 1.4 Fiesta Titanium automatic, with <9k miles on the clock.

I noticed a low buzzing/humming noise at the end of any journey which an internet search revealed to possibly be a problem with the climate control, so I've booked the car in for a check under the warranty.

More pressingly, however, is that after 4 days of use (mostly commuting) the trip computer is showing me 24.9 MPG after 100 miles. The car is advertised at an average mpg of 44 - I'm easy on the pedal and not using the downshift and can't figure out why the MPG is < 25.

Any ideas?

(if you want any more info I can give it)

Hi Alan,

Welcome to the club.

With regards the low MPG< you have to bear in mind that this is an average calculated between resets. For example, if the former owner had a right foot of lead weight, then the MPG will be lower, if they never reset this over a period of years, then this will be difficult to shift, and will show you wrongly the output.

The best thing you can do is get the car a good service (new oil and filters) which will ensure that you get the best health for your car. Then, disconnect the battery of the car for a half hour. This allows the ECU to reset the values and puts the car into a learning mode, which means that you can train the car to your driving standards.

For example, if you also have a lead weight foot, then your car will be trained to put more fuel in to get max performance. Likewise, if you drive like miss daisy on a Sunday afternoon, then your car will be trained to use fuel sparingly and will try to get you to your desitnation with more fuel than you started with :p

Now, once you reset the car, it takes a good 2 - 3 tanks of fuel for it to start adapting, so the fuel use and general range may seem poor at the start, dont worry about this it should improve.

If however after several tanks you still have a poor fuel economy, you would have other issues that need to be explored. If you have smoke, then you could have a blocked EGR and/or a leaking pipe or hose causing less efficiency.

I bought my car at the start of the year, I could barely get 300 miles out of it, after a basic service, changing a few filters, blanking the EGR and fixing a leaky pipe, I could (if I really pushed the car to its last drop) get around 500 miles now. I would be shocked if you cant do the same :)

Thanks for the thorough reply. I'll try and drop a little more info to see if that helps.

The trip computer was reset the morning I bought it and it showed me 25.2 mpg for the 3 days I'd driven it. I reset the trip again this morning and drove to work and it showed me 24.9 MPG for my 10 mile drive.

The car was serviced prior to me buying it but as I'm taking it in again in a few weeks what are the things you would recommend I mention in order to try and improve the MPG?

OK so it sounds like you would benefit from the car retraining.

You would ideally need an air filter replacement, a check of all hoses to ensure you dont have any cracks or breaks in the air lines. An oil and filter change will make the engines work easier as it will be clean and hopefully not "polluted"

These coupled with a battery disconnect and retrain should help.

What is the engine? is it a petrol? I know you would get less than the quoted figures, but I wouldnt expect half!

Just try disconnecting the battery, then touch the positive and negative terminals for a few seconds, leave the car unplugged for a half hour then plug it back in. Run through the retrain process (drive it how you normally would / will) then just see how it goes from there.

I have a full warranty on the vehicle and it was only purchased 4 days ago so would you expect a 'car retraining' and filter replacement etc. to be covered within the warranty?

The engine is a 1.4 petrol, with an auto geabox (which means it's definitely not my fault!).

consumables normally are not covered by any warranty. the retraining also is just the car adjusting to a different driving style. Like I said, if its former owner was Collin McRae or Lewis Hamilton, you expect your driving styles to differ.

I would ask the garage what service was done and what items were replaced. Often just an oil topup and a check of when the oil filter was last changed can be used as a copout to say they have "completed" a service.

Hello fellow auto owner. Also to bare in mind is pre 2012/3 fiestas have an old school 4 speed automatic which isn't know for good fuel economy.

My mpgs fall through the floor during these winter months when doing short city stop & go commutes from a cold start. As James has said it should improve over time, and as daft as it sounds my mpg is much better in the summer months.

To be honest though if you're looking for good fuel economy from the 1.4 petrol 4-speed fiesta, you're going to need a steep decline, and a strong tail wind lol.

Having said that I think my best ever reading was something like 48mpg - but that was on a single journey, rather than an average over a whole tank of fuel.

Post facelift (auto) fiestas now come with Ford's Powershift, a 6 speed twin clutch automated manual gearbox which gives much better mpgs than it's predessor.