[cellsafemode]

40.8 mpg! My best 50 on way to Peoria Arizona from Orange county California.

That's with traffic, rain, and temps around 65-70.

I was getting sustained 30mpg cruising at 90mph.

This car is amazing at gas mileage if you let it be.

A 366 mile trip across mountains and in traffic. Only took a little more than half a tank of gas.

[bishopski]

36.9 on my first long trip of 60 miles. Only 521 miles so far and my average is 31MPG.

[wjmeyer]

After a fill-up, I calculated my city mileage at 24 mpg with the dashboard computer telling me it was just over 25mpg. GM should be able to do software design with better than a 5% error margin.

[cellsafemode]

The doubters can't argue that the OEM has an incentive to lie about fuel usage to make themselves look better by 'proving' it using the measuring device a gas station uses to charge you on how much fuel you are using. They have just as much incentive to lie about how much fuel you are pumping.

1 mpg is certainly within the margin of error of filling your tank since you are never able to accurately start and stop at an actual known amount of fuel used, since you depend on either meters you don't trust and gas tanks with inaccurate meters such that it's not possible to stop when the fuel gauge says a given level and translate that into a specific gallon figure. On top of that, every gas station nozzle stops at a different level. 1mpg is literally 100 ml when you are getting close to 40. Your difference can be vapor in the tank.

Whether or not the numbers are precise to the mile can be debated until someone mythbusters the car on a known track with a known amount of fuel with all other factors accounted for.

It doesn't really matter though. You can't lie about the incredible distance you can travel at high speed in this car without needing to refuel, or the way it performs when you don't care about mpg's.

[bishopski]

My first 2500 miles has resulted in 30.2mpg. I check the numbers each time and find the results very close to actuals.

[jingaling]

I drove from Diamond bar, CA to Oklahoma city and got about 30mpg. I was doing around 80mph the whole way

[CMCamaro]

Originally Posted by wjmeyer

After a fill-up, I calculated my city mileage at 24 mpg with the dashboard computer telling me it was just over 25mpg. GM should be able to do software design with better than a 5% error margin.

I would guess the car calculation is more accurate. Considering your car probably has the bsfc curve as part of the software to calculate MPG.

[GTIanZ28]

Originally Posted by cellsafemode

This is not going easy on the commute.

Mine is similar.

Ill take a picture of mine at lunch. It's rather pathetic. So much so that I wonder if I should have just bought the SS. Can't imagine that it would be much worse.

I was only getting 18-19 mpg in a VW GTI so it is my crappy commute.

Lifetime of my car (have never reset trip B)

[SR 33]

Better than I ever expected

[Need4Camaro]

I managed to get 41 MPG over a 50 mile stretch max in a 2017 A8 V6 after figuring out how to precisely activate 4 Cylendars at-will instead of 6 and changed my driving habits to minimize the amount of throttle I had to use while maximizing my over-all speed .. For example, going down hill I would just lightly apply the throttle and let her climb up to 85 - 90 MPH and then keep my foot mildly applied and gradually lose that speed slowing back down to about 65 - 70 as I climb up hill meaning I didn't burn any extra gas to climb the hill. As for the actual MPG counter, it IS slightly off but not by alot. When it reported 40 MPG, I literally (no exaggeration) drove about 400 miles and still had half a tank left.

[bishopski]

Originally Posted by Need4Camaro

I managed to get 41 MPG over a 50 mile stretch max in a 2017 A8 V6 after figuring out how to precisely activate 4 Cylendars at-will instead of 6 and changed my driving habits to minimize the amount of throttle I had to use while maximizing my over-all speed .. For example, going down hill I would just lightly apply the throttle and let her climb up to 85 - 90 MPH and then keep my foot mildly applied and gradually lose that speed slowing back down to about 65 - 70 as I climb up hill meaning I didn't burn any extra gas to climb the hill. As for the actual MPG counter, it IS slightly off but not by alot. When it reported 40 MPG, I literally (no exaggeration) drove about 400 miles and still had half a tank left.

Its funny how many of us drive in manual mode. The gearing in the A8 seems off to me. Constant shifts at speeds about 60 without driving in M8. Still love my car! I am just guessing the the government mandated MPG thing.... Same reason Ford still throws 2.73 gears in pony cars.

[Need4Camaro]

Originally Posted by bishopski

Its funny how many of us drive in manual mode. The gearing in the A8 seems off to me. Constant shifts at speeds about 60 without driving in M8. Still love my car! I am just guessing the the government mandated MPG thing.... Same reason Ford still throws 2.73 gears in pony cars.

I believe the V6 models mostly came with 2.77 rear axel gears. Mine did, I'm sure there are exceptions (1LE, RS maybe, ect) but mine seems a bit laid back. The shifting on it is alittle weird.. It is almost like there are gears between gears and that its alittle too closely geared in 1st, 2nd with a big jump in 3rd then 4th thru 6th are almost useless and 7th and 8th have too big of a gap...I can't even get into 8th gear until 53 MPH absolute minimum and I feel like it holds 3rd gear and 7th gear alittle too long ... Although I don't think its the gearing that prevents it from getting good gas mileage, but how the PCM shifts. If you're on the interstate, especially while using the cruise control..you will notice it downshift from 8th to 6th on the slightest incline. This isn't really necessary, drive it in manual mode and it will hold 8th gear all day long up a 5% grade as long as you're doing 70 + MPH and yes..it DOES get better mileage even going up hill in 8th than it does by downshifting to 7th or 6th.

The thing about manual mode, is it disables Active Fuel Management when you downshift to a lower gear and it will not re-activate until its put back into auto mode. So the trick is, put it into manual mode but KEEP it in 8th gear (or 7th if you're on the street, just DON'T downshift), feather the gas to keep it using 4 cylendars, if acceleration is necessary try to do it WITHOUT downshifting. If downshifting is necessary, downshift and get up to speed quick, then switch back to auto mode and wait for it to select 7th or 8th gear and active fuel management will be re-enabled, switch back to manual mode and you're still able to use active fuel management UNTIL you downshift.. Thats how I managed to get 40 MPG out of the Automatic.

[RobertSmith]

Can we conclude that A8 gets better gas mileage than the M6?

[b0bsaget007]

2.0T 6M here. I'm genuinely impressed that some of you guys are getting better gas mileage than I am (26 MPG average per tank, ~30 MPG on my 39-mile round-trip commute to work). You guys using 87 or 93 octane?