How accurate are mpg figures?

[Anonymous]

I've noticed that my (small) central display figures for mpg are very erratic. I clocked up 44.1mpg on a motorway run but was averaging around 37mpg on mixed driving, mostly around town and dual carriageway. Then a few days ago I zeroed the reading again after filling up (the tank, not my eyes) and clocked 42.4mpg driving home at night on dual carriageway but over the next few days it's dropped to 33.4, albeit just small journeys around town of around 2 miles at a go. Is this normal or faulty? About 700 miles on odometer.

 

[FGRob]

Town work will drop you average quickly, I've had mine down to 9 mpg with a heavy right foot, so it will be up and down. The only time I've seen a steady figure is on a good run when using a complete tank full, I tend to use the first setting on the computer for running around - real time, the second one is when I fill up to get and average for the tank full and the third for work trips which I charge to the company, you will be surprized at the difference between the 3, especially 2 & 3.

Rob. :crazy:

 

[RCZ1]

I've found this too L. Town driving really makes the MPG fall. Country roads and motorway driving produce good MPG. I've only done 300+ miles in mine and yours has not done too many so the engine is still bedding itself in, so once it's settled down its MPG will be more realistic. I don't think it anything to worry about.

 

[Anonymous]

Thanks for the replies, folks. Most reassuring. I had switched off to the blank screen (apart from the gear change indicator) because it was getting on my WICK :lol: :lol: :lol: .

 

[FGRob]

WICK

Is that a town or candle :dance: :lol: :lol:

 

[Anonymous]

Hi, dont get my RCZ till Tues, but can tell you from driving my other car that the MPG can vary considerably depending on the length/type of journey. Short journeys around town will return the poorest MPG figures, because of stop/start, constant gear changing etc.

The best figures will be on a good long run on a motorway at a steady speed of 70mph. I work 10 mins from home & my average mpg on my 3.2liter diesel Merc, is around 29.1, but if we travel up to the Lake District or better still The Highlands of Scotland, early in the morning when traffic is light, we have clocked 47.7mpg. However, that can come down drastically by the following day, if our driving pattern changes again ie hills, town etc!

Hope this helps! Happy motoring :thumbup:

 

[Anonymous]

WICK

Is that a town or candle :dance: :lol: :lol:

:lol: :lol: :lol: I think it's a colloquialism peculiar to Ireland :dance:

 

[Anonymous]

Hope this helps! Happy motoring :thumbup:

Hi Marthamay22, thanks for your detailed reply. I did know that different types of driving produced differing performance but this is the first car I've had that actually showed the mpg and I just wasn't sure if it was accurate or faulty.

Best wishes for the big hand-over on Tuesday.

 

[Anonymous]

Hi Bangor
The initial display is the MPG you are getting at that moment.
The second screen shows the first Zeroed miles MPG and the third screen the second zeroed miles.
My readings, after 2900 miles are whatever my foot is doing, 47.6 mpg at 2300 miles and 47mpg at 1200 miles.
That shows the lighter foot whilst running in.
Oh let's not forget speedos are 5 to 10 % out and therefore the readings are wrong and we have services earlier than we should, just a pet hate!
Hope that helps

 

[Anonymous]

Hi Bangor
The initial display is the MPG you are getting at that moment.
The second screen shows the first Zeroed miles MPG and the third screen the second zeroed miles.
My readings, after 2900 miles are whatever my foot is doing, 47.6 mpg at 2300 miles and 47mpg at 1200 miles.
That shows the lighter foot whilst running in.
Oh let's not forget speedos are 5 to 10 % out and therefore the readings are wrong and we have services earlier than we should, just a pet hate!
Hope that helps

Hi RCZ White. Thanks for the further info. That first screen seems to leap all over the place so I ignore it and use setting 1 of the 2 screen option. As I'd said before, this is the first car I've had that gives you a blow-by-blow record of how heavy your foot is (my dad always told me I'd a very heavy right foot :lol: ) so I'll just have to NOT let it annoy me when I see the figures plummeting. I didn't buy the car for the mpg anyway so I'm in no way disappointed, no matter what it ends up delivering.

 

[Anonymous]

Thanks for the replies, folks. Most reassuring. I had switched off to the blank screen (apart from the gear change indicator) because it was getting on my WICK :lol: :lol: :lol: .

I will switch this off too. I had an old BMW 318 many years ago tha thad this display and it couldn't be switched off :thumbdown: I stuck a Band Aid over it in the end. The MGZTT has this and I only ever use the average MPG and not the actual mileage.

It's better just to enjoy the car without worrying about how much it's costing each mile :lol:

Cheers

Dave

 

[Anonymous]

It's better just to enjoy the car without worrying about how much it's costing each mile :lol:

Cheers

Dave

I couldn't agree more :thumbup: . Thanks for the reply although I think I'll avoid the bandaid route :lol: .

 

[Anonymous]

I think MPG wise, over 4k, our diesel averaged 47mpg, and currently over 2k our 200hp is averaging 28.9mpg. Not too bad considering it does a lot of town, and some fast back road driving, with a mix of drivers.

 

[Anonymous]

Hi Bangor
The initial display is the MPG you are getting at that moment.
The second screen shows the first Zeroed miles MPG and the third screen the second zeroed miles.
My readings, after 2900 miles are whatever my foot is doing, 47.6 mpg at 2300 miles and 47mpg at 1200 miles.
That shows the lighter foot whilst running in.
Oh let's not forget speedos are 5 to 10 % out and therefore the readings are wrong and we have services earlier than we should, just a pet hate!
Hope that helps

Hi RCZ White. Thanks for the further info. That first screen seems to leap all over the place so I ignore it and use setting 1 of the 2 screen option. As I'd said before, this is the first car I've had that gives you a blow-by-blow record of how heavy your foot is (my dad always told me I'd a very heavy right foot :lol: ) so I'll just have to NOT let it annoy me when I see the figures plummeting. I didn't buy the car for the mpg anyway so I'm in no way disappointed, no matter what it ends up delivering.

Exactly Bangor RCZ. If you were really concerned about fuel consumption you would have bought a diesel and feathered it around the countryside. But you didn't. You bought the petrol and you admit to a big right foot. Just give it stick and treat the mpg display as a guide to how well you are doing that. That is, the lower the better!!!! Set youself a challenge - see if you can get it below 10 mpg :crazy: (as an aside oh how good it is to hear of mpg again. Down here in oz we use litres per hundred kilometres. What a stupid, stupid measure that is). :roll: :roll:

 

[Anonymous]

Exactly Bangor RCZ. If you were really concerned about fuel consumption you would have bought a diesel and feathered it around the countryside. But you didn't. You bought the petrol and you admit to a big right foot. Just give it stick and treat the mpg display as a guide to how well you are doing that. That is, the lower the better!!!! Set youself a challenge - see if you can get it below 10 mpg :crazy: (as an aside oh how good it is to hear of mpg again. Down here in oz we use litres per hundred kilometres. What a stupid, stupid measure that is). :roll: :roll:

Hi aussiercz, that's some challenge...below 10mpg!!! :lol: Seriously don't want to go there! By the way, have you exchanged pleasantries yet with Brett, a fellow antipodean? He's a newbie and I told him to contact you and you could keep each other's spirits up waiting for your babies like expectant fathers :thumbup:
Lorraine

 

[Anonymous]

Exactly Bangor RCZ. If you were really concerned about fuel consumption you would have bought a diesel and feathered it around the countryside. But you didn't. You bought the petrol and you admit to a big right foot. Just give it stick and treat the mpg display as a guide to how well you are doing that. That is, the lower the better!!!! Set youself a challenge - see if you can get it below 10 mpg :crazy: (as an aside oh how good it is to hear of mpg again. Down here in oz we use litres per hundred kilometres. What a stupid, stupid measure that is). :roll: :roll:

Hi aussiercz, that's some challenge...below 10mpg!!! :lol: Seriously don't want to go there! By the way, have you exchanged pleasantries yet with Brett, a fellow antipodean? He's a newbie and I told him to contact you and you could keep each other's spirits up waiting for your babies like expectant fathers :thumbup:
Lorraine

Yes I have. Brett pm 'd me and we've started a conversation. I suspect that Brett may be able to get below 10 :lol: :lol: :lol: mpg

 

[Anonymous]

ps Bangor RCZ Another challenge for you. I would love to know which of my posts caused you to conclude that I am a bloke.

 

[Anonymous]

ps Bangor RCZ Another challenge for you. I would love to know which of my posts caused you to conclude that I am a bloke.

Oops ! That's just me assuming that most forum members are male until proven otherwise . So...are you?

 

[Anonymous]

ps Bangor RCZ Another challenge for you. I would love to know which of my posts caused you to conclude that I am a bloke.

Oops ! That's just me assuming that most forum members are male until proven otherwise . So...are you?

Don't worry BangorRCZ - I thought RCZ was a bloke too - was mortified when she put me right! Maybe we should do a poll of how many male members (oh god that sounds so wrong!!! ) and how many females there are on the forum!

 

[Anonymous]

I meant RCZ1!!!

Hard day at work!