Author Topic: MPG Decreased after visit to VW garage  (Read 2250 times)

Offline Pixwix

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MPG Decreased after visit to VW garage
« on: 05 March 2017, 14:35 »
I took my car into the dealer the other week to get them to see to a rattle...which they haven't sorted so have booked it in again...however before I took it in I was getting around 30-32mpg. Since taking it in I struggle to get 28mpg - 4000 miles on clock, Gti PP. The long term figure shows 27.1 but says it's for 300 miles, basically looks like it has been reset.
What I am wondering/hoping for is some advice / information I can go armed with. It just seems so strange that it has dropped so much since it was in the garage. It wasn't in for anything mechanical the rattle was around the dash.
Coincidentally the day after I also got low tyre pressure warning.
I haven't checked the mpg the old fashioned way yet but guess I could do that. But I read a few other threads and my previous 30-32 seemed pretty standard.
Any help would be much appreciated.

Offline Watts

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Re: MPG Decreased after visit to VW garage
« Reply #1 on: 05 March 2017, 15:09 »
Sounds very odd. Have you checked your tyre pressures? If they are low that will increase your fuel consumption. Also the long term does reset although I'm not sure after how many miles but sounds possible it was before you went to the garage. Failing all that you could just ask them if your car received any updates when it was in but my feeling is there are other factors at play. Hope you figure it out. :smiley:
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Offline SRGTD

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Re: MPG Decreased after visit to VW garage
« Reply #2 on: 05 March 2017, 15:12 »
Assuming the car data functionality that can be displayed on the infotainment screen in the Golf works the same way as it does in my Polo GTI, the long term data information resets itself back to zero after 100 hours of driving time.

Are you sure yours didn't reset itself 300 miles ago, which could account for the step-change in the long term mpg figure. Has your driving during the last 300 miles been mainly short journeys which could account for the lower long term figure? What is the 'number of hours driven' time shown as within the long term vehicle data? If it's low, then this might confirm the car has reset the data. Suggest you manually calculate your mpg for the next couple of tanks of petrol to see what the true mpg is.

As far as the tyre pressure warning is concerned, it may be a coincidence that has happened a day after your car was at the dealer. Was one or more of your tyre pressures low compared to the recommended pressures, hence the warning being triggered? Are your tyre pressures normally constant at the recommended pressure when you check them regularly?
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Offline Pixwix

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Re: MPG Decreased after visit to VW garage
« Reply #3 on: 05 March 2017, 16:25 »
Thanks for the responses...all good questions and which my other half asked too...I just ignored him though but will take more notice of yours!
Am going to double check all pressures later this aft, indicator was just low pressure in one.
Long term mileage is actualllt showing at 433 and 23.20 hour and 27.1.

Offline Watts

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Re: MPG Decreased after visit to VW garage
« Reply #4 on: 05 March 2017, 16:53 »
27.1 does seem low for a long term average however if you divide your miles by the time driven it averages out at 18mph therefore by that seems entirely possible. My long term currently stands at 1800 miles over nearly 80 hours giving an average speed of about 23mph - my average mpg is 33 but although my speed is low it tends to be steady with minimal stopping. If yours are slow and in traffic, plus it's been cold weather with all the added electricals on more (heating, heated windows, seats perhaps some stationary running whilst defrosting?) so doesn't sound like something is likely to be wrong.

As for the ignoring your OH's good suggestions and help in favour of strangers on the internet, I feel for him as that's what I have to endure at home too :sad: :laugh: :rolleyes: :whistle:
2019 Oryx White 5dr TCR.

Was - 2015 Tornado Red 3dr GTI PP, manual, Santiagos, Audi short shifter.

Offline Pixwix

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Re: MPG Decreased after visit to VW garage
« Reply #5 on: 07 March 2017, 20:49 »
 :grin: thanks Watts...should have seen his face when I said I had posed the question on the forum!
Anyway turns out the gauge I was using was not too accurate so have reset all tyres too correct pressures and will drive for the next few weeks with a cool backside and wipe my own wing mirrors and see what happens.....30mpg will not be beyond my reach. Btw my Think Blue screen (or whatever it's called) shows 31mpg so i know I've been there. But too honest very rarely go that screen...too blue!

Offline Degsy

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Re: MPG Decreased after visit to VW garage
« Reply #6 on: 11 March 2017, 08:39 »
Hi
This subject caught my eye as the same thing happened with my neighbours Audi
Apparently it was due to an software upgrade done by the garage,
Neighbour was not impressed and has since changed the car to something different
Has anyone else heard of this ?

Offline Pixwix

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Re: MPG Decreased after visit to VW garage
« Reply #7 on: 11 March 2017, 19:40 »
They assure me no update done..and when I went to collect it they showed me on test drive they got 33mpg..but I left it with them as rattle still not sorted so have yet to see what I can get.