A35 AMG poor fuel economy

[Mahoney79]

Few months ago I bought a 2019 a35 amg with only 20k miles on it. In the specs it should do around 30 mpg driving in town/city and 46 on the motorway. For me 30/35 mpg is the average in the motorway driving with cruise control at 75mph and everything set to basic. In town the car has an average of 20 mpg. I've heard a lot of other people with the same car doing a lot more mpg than me using the same engine setting of me. What could be the issue? Could it be due to the oxygen sensor or a remapping? My car had 5 previous owners and I'm afraid some of them messed up with the engine. What are your thoughts?

 

[fabes]

Codes, codes and codes

And tyre pressures, sticking calipers and service history

Would all be good starting points if others are genuinely getting better mpg.
It's also cold(ish) at the moment so will impact mpg.

But do get codes read and on STAR if possible as that may / should (but I don't know) be able to detect a remap from live data.

That will cost you c£70 in most cases I suspect, but worth it if you intend to keep it for a while, debatable if not ...

 

[Mickyh7]

My son-in-law had one of these for a couple of years.
From new.
22-23mpg.
Once, he got near 30, on a 200 mile run.
It's a performance car.
It is what it is unfortunately.
Never, ever believe manufacturers mpg.

 

[SpikyMikey]

My son-in-law had one of these for a couple of years.
From new.
22-23mpg.
Once, he got near 30, on a 200 mile run.
It's a performance car.
It is what it is unfortunately.
Never, ever believe manufacturers mpg.

^This.
If you blank off the radiator grillle, pull the door mirrors in, pump the tyres up to 200 bar and find a long flat straight piece of road on a cold day with no wind, then you might begin to get close to the official mpg figures.

 

[Mahoney79]

My son-in-law had one of these for a couple of years.
From new.
22-23mpg.
Once, he got near 30, on a 200 mile run.
It's a performance car.
It is what it is unfortunately.
Never, ever believe manufacturers mpg.

I know manufacturers data are based on optimal condition but the better fuel economy I'm talking about is from people using the same car on a daily basis. I asked the same question on a Facebook page and people are on a better consumption than me. I know that it's a performance car but it shouldn't have this kind of fuel economy if not pushed all the time...at least not this difference

 

[DSM10000]

I

heard a lot of other people with the same car doing a lot more mpg than me using the same engine setting of me.

Anecdotal evidence is pretty useless as you have no idea if it is true or the driving styles.

Manufacturer figures are usually achieved on a rolling road under laboratory conditions.

As said, you bought a "performance car ", not one optimised for economy.

 

[Mickyh7]

I know manufacturers data are based on optimal condition but the better fuel economy I'm talking about is from people using the same car on a daily basis. I asked the same question on a Facebook page and people are on a better consumption than me. I know that it's a performance car but it shouldn't have this kind of fuel economy if not pushed all the time...at least not this difference

I appreciate your comments, however if your not used to a performance car it can be a different learning curve.
They only need the slightest touch on the accelerator to go!
I've had a lot of 3.0 litre cars, the way I drove them made a huge difference.
Keeping them in sport mode is a big problem for fuel consumption.
Or perhaps its had an aggressive remap?
Good luck with it.

 

[Mahoney79]

I appreciate your comments, however if your not used to a performance car it can be a different learning curve.
They only need the slightest touch on the accelerator to go!
I've had a lot of 3.0 litre cars, the way I drove them made a huge difference.
Keeping them in sport mode is a big problem for fuel consumption.
Or perhaps its had an aggressive remap?
Good luck with it.

Most of the time I don't drive hard...cruise control at 75mph and on eco setting. That's why I wonder.
Thank you for your replies

 

[Mahoney79]

I

Anecdotal evidence is pretty useless as you have no idea if it is true or the driving styles.

Manufacturer figures are usually achieved on a rolling road under laboratory conditions.

As said, you bought a "performance car ", not one optimised for economy.

They shared screenshots of the mercedes me app with the average consumption so it's true. I'm only wondering as I don't tend to push the car...only every now and again. Most of the time I'm on the motorway on 75mph with cruise control and everything set on basic

 

[DSM10000]

They shared screenshots of the mercedes me app with the average consumption so it's true. I'm only wondering as I don't tend to push the car...only every now and again. Most of the time I'm on the motorway on 75mph with cruise control and everything set on basic

You believe the Mercedes Me app? The only true mpg is when measured brim to brim.

 

[Bobby Dazzler]

Comparing fuel consumption with another driver, in another car, on another journey, on a different road, in different weather, at a different time of day, with a different journey le gtg. with a different driving style will be futile.

To improve your fuel consumption on the Norway, reduce your speed and don’t use the cruise control, so that you can back off the accelerator . Does you car have glide mode, if so then your car will effectively coast.

 

[Mickyh7]

To be fair, the Mercedes me app didn't update the mpg very often on my c300 amg.
Not the best app in the world.

 

[ALFAitalia]

Never had a car that I could not get close to or equal the claimed figures...my 528i could better them with a bit of effort.... its about driving style, smoothness, avoiding braking as much a possible and not having a right foot that weighs as much as Thors hammer! But I don't drive like that much....boring! But it is usually possible.

 

[kcsun]

Personally if your car has had 5 owners, I would suspect someone has put a map on it at sometime, perhaps get the main dealer to reflash the ECU although the money it will cost will take many tanks of 98 for payback
As others said, it is a performance car, sit back and enjoy

kc

 

[geoffus]

I agree with the above, try to cruise under 70mph and don’t use your cruise control, that way you can gently accelerate when going up slopes, then back off and coast down.

 

[Mickyh7]

I agree with the above, try to cruise under 70mph and don’t use your cruise control, that way you can gently accelerate when going up slopes, then back off and coast down.

Then you can sell your A35 AMG, and buy a Yaris!

 

[geoffus]

Then you can sell your A35 AMG, and buy a Yaris!

I was thinking more of a Prius.

 

[TrueSpirit]

Mercedes-Benz A35 AMG MPG - Actual MPG from 10 Mercedes-Benz A35 AMG owners

The most accurate Mercedes-Benz A35 AMG MPG estimates based on real world results of 130 thousand miles driven in 10 Mercedes-Benz A35 AMGs

www.fuelly.com

I'm with you OP, your fuel economy seems a touch low. What tyres do you have on and what psi?
Don't feel too bad, my 6.2l e63 was getting similar fuel economy as my 4.0l is and thr 6.2 definitely gives far more smiles per gallon

 

[UKGTC]

100% the advice on tyre pressures make a fair bit of difference as can servicing but I'd expect a A45 S to get 25-30mpg. Cruise control can most certainly waste fuel compared to careful driving because even adaptive cruise control doe not anticipate anything over about 100m ahead. I recently did a 160 mile run using cruise and in similar traffic conditions came back without. sing cruise I average 23mpg and without 28mpg, which for a 4.0 V8 was not so bad considering running 325 Cup 2s which aren't the best rated for fuel economy. This was going 75-80mph.

One thing I have learned to live with is the fact no car that goes quick is going to be great on fuel unless it smells of diesel or sound like an electric hairdryer.

My mum drives around in a 14 year old Vauxhall Zafira 1.8 and it does 38mpg average compared to my 24mpg. They spend £200 per month on fuel (£2400 a year) and if I did the same amount of miles I would be spending £274 per month (£3288 a year). When you work out the figures I have to question would I sooner drive a slug slow ugly Zafira or pay £888 more fuel to drive the GTC all year? In reality it is nowhere near that much because I car share to work and only drive at the weekends usually, but I would still make the same decision.