RIBS

So I have had My mustang since April and it is a great car. It's the V6 auto 2.73 gears...I have the MCA package with the 18 inch wheels.

I have almost 9000 miles on it, and the overall mileage is about 22 mpg, and yeah I know that is the EPA average estimate..But I drive about 80% highway!!

I have run it at 72mph with cruise and no AC for hundreds of miles and got 25mpg. I tried long runs of 45, 55, 65mph, never got over 25mpg. Normal highway speeds of 75-80 with AC on drops it to about 22mpg...

I ran it 100% city and got 24mpg for the tank, but when I mix in the highway driving it drops!! What happened to 31 mpg highway? Has anyone seen that??

I did my manual calculations of gas purchased and mileage and it was within 2/10 mpg with the computer...

The dealer says it wont be broke in till 10,000 and I should not worry...

steven46746

Hmm, I can get(according to the computer) 26-27 highway with my 5.0 and 3.73 gears. Mid to low 20's sounds way off for a v6 with 2.73. 6300 miles.

Ajcruz1

Do you constantly reset the computer mpg calculator? I usually reset it at every other fill up. V6 with 3.31 and I get 20-22 city and 27-28 highway but mines is also not broke in. I've had it since begining of July and only at 2K mi.

newpony

Where do you live? Lot of hills in your area? Your MPG is way off I think for a V6 auto with 2.73. I live in Mass (no flat like Florida, Vegas etc) have V6 manual, 3.31, 19 inch wheels, Summer tires, spirited driving, 80% highway, averaging speed 80 mph and I'm averaging around 24-25 MPG (combined) consistently .

Ethanjbeau

Don't trust the computer. Calculate it yourself.

tukatz

Mine is a V6 auto with stock 2.73 rear end and stock 17 wheels and Michelin Energy Saver tires. It has a little over 10,000 mile now. On a recent road trip of almost 2,000 miles it averaged 28.15 MPG. The fist leg of the trip was down I5 from near Tacoma to near Grants Pass, OR. I ran low 70s in Washington and upper 60s in Oregon. That leg was 379 miles and I averaged 32 MPG. These are calculated numbers using trip meter mileage and gallons pumped to refill the tank. There was some spirited driving on California Hwy 1 and upper 70s on the way home in Washington.

radioguy1

Not very good mileage, especially your "highway driving." The computer is a bit "flaky" so I would always fill the tank and compute the mileage manually. I had a 2011 Mustang V6 vert and it did much better then your numbers (Traded it last year for a 2013 GT vert). See the attached 2011 Mustang V6 vert mileage chart. The first real highway trip was at 5300 miles and the mileage was over 31.2 MPG. Whom ever you talked to at the dealer, should be put on your "do not talk to again" list.The user manual has data on "break-in." If I was really cruising on the highway - 60, 70, 75 mph - I always got over 28 MPG and often over 30 MPG.

Moustang

I've seen this issue before. I've seen the problem corrected by disconnecting the battery overnight and allowing the computer to reset itself.



FYI, my 2012 V6 with 2.73 gears manged to average 34mpg between Plano and Corsicana in Texas. That's 78 miles worth of driving at 70-75mph including driving straight through downtown Dallas at 2PM. I've averaged 32mpg between Plano and Katy, a trip of nearly 300 miles. You should be able to get at least 29 with the air conditioner running from yours.



This is of course assuming you don't live someplace like Boulder, Colorado. At high altitude you're going to get a lot worse gas mileage.

tukatz

My computer always overstates the fuel consumed and understates the MPG, but the differences are fairly small. I use the display numbers only as a guideline while driving, but always compute actual numbers manually.

Ltngdrvr

Dealer is full of poo about it not being broken in until 10K, with 9K on your car now it is well broken in.

Driving style is probably your problem, most fuel economy issues are corrected with only a driver mod.

For best mileage you have to drive like grandma, no fast starts, and SLOW DOWN!!!

Not the fun way but it's the gas mileage way...

Moustang

Nonsense.

I routinely drive fast. It's rare that someone is in front of me leaving a red light. I definitely do NOT "hypermile" my car. I do however average 24mpg with 80% of my driving in north Dallas rush hour traffic.


I have also personally experienced a 2013 V6 Mustang that did precisely what the OP is complaining about. Noticably worse gas mileage than my 2012.

Uncle Jonfrey

This is driving 60-65 mph in a 5.0 with 3.73's, A/C on blast mode. Notice the 5 minute history, there are periods when I got better than 28mpg. Surprised me enough to snap a quick pic of it and text it to some V8 mpg haters I know

CiniZter

is 60 - 65mph the better mileage speed range... cause in my part of town i have only two options... either it is 35 or it will 75....i only get 23 mpg on my 5.0.

JimC

Hand calculation is just an estimate you realize. You assume that every time you fill up you are putting exactly the same amount of gas in the car. But temperature, the flow rate on the pump, sensitivity of the pump, vapor in the tank, all affect how much you put in with each fill up.

The 2013+ though the computer is measuring how much fuel it sends through the injectors as well as how many miles you travel. It isn't assuming that the same amount of fuel is put in the tank. I find that the computer and hand calculation is always close (have an app on the phone that I use to track fuel). Both are no more than a close estimate, with I suspect a little more accuracy on the computer because of the values it measures for its computation of MPG.

tukatz

I understand what you are saying, but if we are talking a V8 cruising at 1,500 RPM for a six hour road trip that's 3,600,000 injector squirts. If the number the computer has been programmed to use as fuel consumed per squirt is off by an almost unmeasurable amount, over the course of those 3,600,000 squirts the volume will add up.
When I'm on a road trip I record the details of each fillup and enter them into a spreadsheet. The amount I pump into the car is consistently less than the amount consumed per the computer, and the spreadsheet calculated MPG is consistently higher. In both numbers, the difference is small, but it is there.

steven46746

After about 40 miles

RIBS

I am going to try diconnecting the batttery..
FYI
Yes I reset trip A and the MPG screen at every fill up.
Trip B has not been reset since car was new.
The trip B and my manual calculations are within 2/10 MPG of each other..
22.4 for computer, 22.6 for manual calc over 5000 miles of writing gas purchased/odometer in a book at every fillup.
There are some minor dips and hills but nothing to speak of...

For fun, I have set cruise on flat highway to 45, then reset mileage calculator, and done the same at 55, 65, 75. Mileage starts up around 25 or so and drops to 22 at the higher speeds....I have done the same with cruise off...same result.

Tominkc

I have a 2012 GT 5.0 with 3:73 gears, 6 sp manual. I drive alot of hiway miles during the week than on weekends it's more city. And I average around 20.5- 22,8 MPG!! And I do alot of spirited driving on the weekend! I also find that I get alot better gas mileage doing 80 mph than doing 65 mph! I guess that's where my engine runs the best

Moustang

Definitely give that a shot. I've heard several people say it works.


That is staggering.

In my V6 with the same gears I get over 40mpg at 45 in 6th gear on a flat road. Even at 70 I average over 31mpg. Somewhere between 70 and 75 I hit a sweet spot and can get as high as 34mpg.

jtb3

That is staggering.

In my V6 with the same gears I get over 40mpg at 45 in 6th gear on a flat road. Even at 70 I average over 31mpg. Somewhere between 70 and 75 I hit a sweet spot and can get as high as 34mpg.
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I have a 2014 V6, auto w/2.73 rear with 3700 miles and am averaging about 25 MPG in mixed driving with some spirited driving added in.
If I really want to, and my right foot doesn't want to, I can get 34-36 MPG
on a flat road holding a steady 60 mph.......31-33 MPG at 75 mph.
Tires inflated to 36 psig, windows up, no A/C and car waxed.
A vert, especially with top down or windows down, under inflated tires, etc, will cause drag and pull down the MPG's. If you can find a gas station selling pure gasoline without the fermented corn juice in it.....that alone will give a few extra MPG's!