Very poor MPG

[Jammillar]

I recently purchased a 1.4 TSi bocanegra, 10 plate with 35k on the clock. Since I've had it I haven't driven it hard, only backwards and forwards to work, a 20 mile round trip mostly national speed limit but rarely had chance to take it over 60mph, but it's only showing an average of 31.5mpg on the digital display. When I'm meant to be getting a combined average mpg of 44.1. Any ideas what could be causing this because no matter how gently I accelerate and stay around 55-60mph it doesn't seem to go any higher than 32mpg?

 

[Scott Millar]

A simple solution might be to change the air filter? Seat don't change them in the service schedule until 60k but i changed mine at 30k as it was looking rather clogged up. Seemed to improve my mpg a bit.

 

[Big-Pete]

its cold. its gunna be crap on fuel

 

[Ash Rayner]

I second Pete my boc comes up with the exact same but during summer I've had 51mpg from the same trip

 

[Gorbstein]

Is it due a service? How is performance otherwise?

Some things to try:

Air filter, pennies to replace.
ECU reset (not sure of best way to do this on Mk5, usually just yoink the negative terminal on the battery but make sure you have your radio code).
Soft tyres?
Brakes, are they binding at all? They will be hot even after a short trip if so.
Check for any holes or leaky gaskets on exhaust.
Brake disc dust shields, are any in contact with the discs?

Not sure if it helps since I've got the N/A 1.4, but to be honest on my daily drive of about 14 mile round trip it doesn't warm up enough to give great mpg, I average about 34mpg. What kind of figures do you get on longer trips? You should get beyond 44mpg easy.

 

[AL90]

31mpg?! How I would love to see numbers that size again.... I sold my boc for a 350z and the 3.5L V6 gives me 22mpg..... but its a lot of fun

31 sounds fine to me mate, when mine was stock I used to get about that. I really wouldnt worry.

 

[Squash man]

Have you reset the MPG figure? There are also two MPG display options. One will give you mpg for current journey (think it resets 2 hours after ignition is off) and the other is the average over something like the previous several thousand miles (probably not the exact figures but I don't own Boc any more to check manual)

If your on the second display the mpg reading will change very little as averaged over longer time. Think you change between display 1/2 with a button under the RHS stalk.

For comparison I drove fairly leisurely on most of my 34 mile return work commute. About 20 miles of that was 60mph dual carriage way. Averaged around 42mpg.

Do a real world check with how much you're filling up if it's still lower than expected.

 

[dm222]

In my last 70KM I have a 30MPG average XD
Only city
1.4 16V

 

[Pimped up vario]

I didn't find that the cold weather made much difference to the length of time that my petrol engine cars took to warm up. My diesel engine cars took much longer to warm up and the fuel economy in them suffered but not so for the petrol ones. 2.5v6 and 1.8t so maybe that's why. I'd go with one of the earlier posts and say filters plugs brakes and bearings. Also the wheel alignment, thread pattern and pressures can have an impact on fuel economy.

 

[Beazy]

I'd third the service and spark plug comments. When were they last done?


I can squeeze 40+mpg out my car on the daily commute, It's around 18 miles to my work from where I live and involves no motorway or dual carriageways just a normal A road and a few towns.

It can do book figures, it's just a pain to make it achieve them.

 

[troupy]

I have now notiched this I had been getting 38mpg easy and even 46 at a granny drive

but now its getting 26mpg......

cold weather is hitting hard...

 

[Stu wiltshire]

I've never seen 40mpg, mine stays around the 35 mpg unless I floor it ofcourse

 

[nightflight]

Ah, stop ya worrying about less fuel economy and just enjoy the performance boost that the cold dense air gives

 

[stu_m]

fuel prices have gone down!.............whats the problem

lol

 

[Stu wiltshire]

This is very true

 

[marklaruk]

My 1.4 sport I feel is absolute dog **** mpg. A full tank gets 300 miles and that's not driving it silly. I may try a couple of the suggestions above.

 

[britishsligean]

You will never get what the manufacturer says, their figures are theoretical based on a certain driving style, everyone is different, plus every town is different and they never factor in the person that breaks for every bend

 

[Arkaig]

I'm getting rubbish MPG too recently, just the cold weather IMO. Regularly got 45mpg, now struggling to hit 35.

The book figures will be with premium fuel, on a flat road, probably with a speed that minimises drag and sits at the engine's sweet spot.

Saying that I find supermarket fuel to give really poor MPG in the cold. Dunno if it's just psychological.

 

[RDD]

I'm getting rubbish MPG too recently, just the cold weather IMO. Regularly got 45mpg, now struggling to hit 35.

The book figures will be with premium fuel, on a flat road, probably with a speed that minimises drag and sits at the engine's sweet spot.

Saying that I find supermarket fuel to give really poor MPG in the cold. Dunno if it's just psychological.

Could be worse, you could have a non turbo 1.4 16v like me and still struggle to hit 40mpg when driving pretty sensibly

 

[davidhf]

On short, non-motorway journeys, using aircon can affect your mpg by as much as 10%.

Try it with and without and see if there is much difference.