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I just bought a 2013 Ford Mustang GT Premium and the fuel mileage is atrocious on it the highest I've gotten in 14 mpg in 6th gear going 60-65 mph down the interstate for 2 hours. Otherwise driving highways and backroads it hovers around 11-13 mpg. And the fuel range is only 150 miles to empty. Could there be something wrong?
Last edited by kiyoshisuno; Oct 2, 2023 at 04:07 AM.
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From: Western NC
That gas mileage is abysmal. Has the engine been modified in any way?
My '14 GT is an A6 and gets high teens (17 -19 mpg) on the 'traffic' days. Highway mileage is always in the low 20's with speeds up to 70 mph. I rarely have a 'lead foot' in either situation. If I did, I might have numbers much worse.
well, I hope you didn't buy a Mustang GT for fuel economy, LOL
but seriously, yeah that is quite low ... I would start by resetting the mileage meter in the dashboard, and check the mileage the "old fashioned way" (fill tank, note odometer, drive a bit, refill tank, check odometer ... difference between odometer reading is "miles" and gallons to fill up is "gallons"; MPG = miles/gallons)
it might be worth resetting the adaptive memory by disconnecting the battery (for about 20 mins) to make sure it hasn't learned anything wonky ... not likely, but easy to eliminate
next I would look at the tune and the modifications -- like NC asked above: what modifications does the car have, and does it have an aftermarket tune to go with those modifications?
well, I hope you didn't buy a Mustang GT for fuel economy, LOL
but seriously, yeah that is quite low ... I would start by resetting the mileage meter in the dashboard, and check the mileage the "old fashioned way" (fill tank, note odometer, drive a bit, refill tank, check odometer ... difference between odometer reading is "miles" and gallons to fill up is "gallons"; MPG = miles/gallons)
it might be worth resetting the adaptive memory by disconnecting the battery (for about 20 mins) to make sure it hasn't learned anything wonky ... not likely, but easy to eliminate
next I would look at the tune and the modifications -- like NC asked above: what modifications does the car have, and does it have an aftermarket tune to go with those modifications?
It has a CAI, ROUSH exhaust w/ a x-pipe, 20 inch wheels, and a performance clutch as far as I know that's all the mods done to it. I just bought it 2 days ago.
Wonder What Rear End Gears are in It! Could Have Been Changed to Who Knows What. What RPM is it Turning At 65 MPH on the Freeway and What Exact Tire Size Do You Have?
We Can Factor From There. If The Speedo is Correct. Might Check Speedo With Phone App if Available For That.
It has a CAI, ROUSH exhaust w/ a x-pipe, 20 inch wheels, and a performance clutch as far as I know that's all the mods done to it. I just bought it 2 days ago.
none of those "should" make a big difference, though the 20-inch wheels could be heavy, which might cause a very small reduction in MPG .... if the tires are substantially larger outer diameter than the original tires, and the speedometer was not corrected, you are traveling farther than the odometer says you are, and that could account for some of the low calculated MPG
Many CAI's requires a tune, so that suggests the car might have an aftermarket tune loaded -- what kind of CAI is it? Did you get a tuner device with the car, or any information about an aftermarket tune loaded in the car?
Wonder What Rear End Gears are in It! Could Have Been Changed to Who Knows What. What RPM is it Turning At 65 MPH on the Freeway and What Exact Tire Size Do You Have?
We Can Factor From There. If The Speedo is Correct. Might Check Speedo With Phone App if Available For That.
Wheels are 285/35ZR20 and at 65 mph in 6th gear is roughly 1800-2000 rpm.
I'm Coming Up With 3.31/3.55 Which is a Semi Low Gear and Would Not Help Mileage . I Did Not Plug in Overdrive First Time Around . The Mt-82 Has a .70 Overdrive. Can Our Members With Lower Gears Verify Similar Results! With Freeway RPM?? Or Am I Still Asleep! 27.9 Inch Tall Tire.
Anywhoo It is A Factor and At Best You Have Mid Range Gears it Looks Like Need To Be Sure of RPM and Sure Speedo is Accurate to get Best Results. A Highway Gear Would Be a 2.73/3.08 For Best Mileage Where a Drag Gear Would Be a 3.73/4.10 Drag Gears Getting Poorest Mileage Best Acceleration.
It's Just a Factor in Your Overall Search. Now if It Had Some Super Low Gears Like a 4.88 or The Like It Would Be a Real Big Factor.
3.31 is a pretty good compromise for highway driving and his cruising RPM is right where it should be, so I don't think that is the issue
my money is on the tune and/or speedometer calibration (part of the tune) and/or some other issue right now
I agree it's Not The Major Factor Just a Good Piece of the Picture To Know and Factor In Total Picture. A Manual Check of Mileage Would be a Better Way of Knowing True Mileage. A Check For Codes Would Not Be A bad Idea and Also a Bottle of Techron For a Little Fuel Card & Fuel System Cleaning Would Not Hurt!
Also if Vin Comes Up Showing Different Ratio Then Factored The Question of Was the Speedo Recalibrated is Addressed. Op Has Left The Building! Will Watch For Vin and Advise! Thanks For the Support Bert!
I agree it's Not The Major Factor Just a Good Piece of the Picture To Know and Factor In Total Picture. A Manual Check of Mileage Would be a Better Way of Knowing True Mileage. A Check For Codes Would Not Be A bad Idea and Also a Bottle of Techron For a Little Fuel Card & Fuel System Cleaning Would Not Hurt!
Also if Vin Comes Up Showing Different Ratio Then Factored The Question of Was the Speedo Recalibrated is Addressed. Op Has Left The Building! Will Watch For Vin and Advise! Thanks For the Support Bert!
3.31 Gears As Per Vin So That Jives With Other Info. So It's Likely Gears are Original and No Speedo Calibration Issues Exist.
I would Get the Fuel Additive Run it Down to No Less Than 1/4 Tank. This Keeps the Junk out of the System and Your Fuel Pump Lasts Longer Due to the Fact the Fuel Cools the Pump and when you Run it to Empty You End up Sucking Air and Wearing out Pump Quicker. After Running the Tank with the Cleaner Fill Up, Drive as Close to a Hundred Miles and Then Refill Noting Total Fuel Used To Fill Back Up and Then Compute Mileage and Compare to Readout.
Then You Have a True Baseline to Go By. Then if You Think You Still Have an Issue You Can Start Chasing. Online Epa Fuel Specs Are Not a Reliable Comparison. Other Owners Would Be a Better Source. So in the Meantime if Any 3.31 Equipped 2011-2014 Gt Owners Out There Have Some Fuel Mileage Figures Please Chime in! In Addition to Nc14!
May Want to Do A 15 Minute Battery Disconnect as Well to Reset Everything! Remember to Drive Nice & Easy During Fuel Trials! Never Fill With Car Running as That Can Cause Issues as Well With System. Also Give the Fuel a Minute To Settle Before Restarting After Fill For Fuel Trials. Sorry I Keep Editing But it's 3:00 Am Here in Ca. And I'm Still Waking Up!
3.31 Gears As Per Vin So That Jives With Other Info. So It's Likely Gears are Original and No Speedo Calibration Issues Exist.
I would Get the Fuel Additive Run it Down to No Less Than 1/4 Tank. This Keeps the Junk out of the System and Your Fuel Pump Lasts Longer Due to the Fact the Fuel Cools the Pump and when you Run it to Empty You End up Sucking Air and Wearing out Pump Quicker. After Running the Tank with the Cleaner Fill Up, Drive as Close to a Hundred Miles and Then Refill Noting Total Fuel Used To Fill Back Up and Then Compute Mileage and Compare to Readout.
Then You Have a True Baseline to Go By. Then if You Think You Still Have an Issue You Can Start Chasing. Online Epa Fuel Specs Are Not a Reliable Comparison. Other Owners Would Be a Better Source. So in the Meantime if Any 3.31 Equipped 2011-2014 Gt Owners Out There Have Some Fuel Mileage Figures Please Chime in!
Mgb,
KC
Will do! Thank you so much i thought i was gonna have to count the teeth on the gear.
let us know after you have reset the mileage meter and done the math manually, if you are still coming up with the same numbers; then we can go from there
Check Out these PDF'S They Have Info On Message Center & Ip Functions
Go To This Section in Second PDF
Instrument Panel Cluster (IPC) Dealer Test Mode
To enter the
IPC
self-diagnostic mode, begin with the ignition key in the OFF position. Press and hold the message center RESETbutton. Turn the key to the RUN position and hold the RESET button until the display indicates ENGINEERING TEST MODE, usuallywithin 3 to 5 seconds. Press the RESET button once to advance through each stage of the self-test. To exit the
IPC dealer test mode,turn the ignition to the OFF position.
NOTE:
If the message center detects a non-resettable fault condition that it is reporting out on such as door ajar, the dealer test modesession cannot be entered until the fault condition has been corrected and the message removed. If the dealer test mode session isinterrupted by the fault condition display (such as door ajar), the session can be resumed by pressing the RESET button.
