help with mpg on my A2

77simon

Member
I just back from 86.2 miles trip mostly (95%) motorway, cruise set on 80 m/h and I'm so disappointed with achived mpg.

I filled it up with 8.63l at morrisons so that gives ~ 45.4 mpg :mad:

I'm so angry about this mpg.

Any advice on what could be wrong with my A2 :confused:

Thanks

Simon
 
Well, economy declines with higher speed, but I would still expect over 50 at that speed.

First check tyre pressures, and maybe run a bottle of fuel additive through the system.
Is your car getting up to 90c? Maybe you have a dodgy thermostat...
 
One thing I've noticed is how much difference adjusting the pressure/position of your right foot on the accelerator pedal makes. I am amazed at how easily it is to go from 50mpg as the current reading down to 24mpg at nothing more then that slight adjustment of how the accelerator is applied.
For reference, I have a daily commute of 150 miles, around 100 of which are mainly free flowing A roads and motorway (I leave early in the morning to avoid most of the M25 stand still) and then the other 50 miles stop/start through London. I regularly achieve around 54mpg which drops to around 52mpg when the M25 is not behaving. Mostly I'm travelling at between 65 & 70ish as I try not to go over the speed limit anymore after gaining a speeding fine. That said, I was still getting at least 52 mpg when my journey increased by an additional 45 miles of motorway each day for about 3 months and I was travelling at 80mph for most of the motorway section.

This last week I tried the same speeds but with slightly adjusting my foot position on the accelerate and thus the pressure applied and have achieved 56mpg with the same travel time for the journey each day. Last April just after buying the car I used Millars for the month and was achieving even better results [note to self - must buy some more] and even managed 70mpg on one all motorway trip in the summer one evening on a 2.5hr trip with perfect driving conditions.
 
I just back from 86.2 miles trip mostly (95%) motorway, cruise set on 80 m/h and I'm so disappointed with achived mpg.

I filled it up with 8.63l at morrisons so that gives ~ 45.4 mpg :mad:

I'm so angry about this mpg.

Simon,

My first question to you would be what do you think your MPG should have been?

At a steady 60 mph on a flat road and no gales blowing, I would see nearly 70mpg displayed on my DIS. At 70 mph under the same conditions, this would fall to under 60 mpg. The decline in mpg is not linear with increasing speed, so your 45 mpg seems to be about right. I presume you encountered a hill or two on your journey? Was your engine stone cold at the start of the journey?

Cruise is for maintaining speed, which is not the same as maximising economy. If you want enconomy, slow down, or don't use cruise AND drive economically.

No need to be angry, there is nothing wrong with your car, just your expectations.

John.
 
dan_b I also thought 50 or more easily, tyres pressure check, I think thermostat works well, how can I check it?

I know the right foot makes a BIG difference Vonnie, and from my experience with cruise control on usually the car use more fuel, but 45mpg!!! even my previous car (2001 passat 1.9tdi 130 with 5 gearbox) did better mpg

Could the air filter have influence?

John probably you are right, engine cold on start and hill was too, next time I try max 70 mph.

Thanks,
Simon
 
Last edited:
Hi Simon,
I use my cruise control for as much of my journey as I possibly can, so don't think its the cruise control making the difference.
Reducing the cruise speed as you've said will I'm sure make a difference though.
Regards Vonnie.
 
Simon,

How about a trip back to Skipton Autos for a 5th gear modification? :D Something to consider if you do a lot of high speed miles.

John.
 
I took all advice, and new mpg is much better town-44.88 motorway-56.14,

that 56mpg I accomplished on trip M62 J20 to M1 J39 ended in Newmillerdam, then this same way back, cruise control on 70mph,


I'm looking forward to 5th gear and aero to help my mpg.
 
Will a dodgy thermostat lead to poor fuel economy as mine needs changing and i have noticed a decline in fuel economy, i thought it just effected what temperature was displayed on the dial?

Chris
 
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