I have a 2006 Mustang GT 5-speed. Fully stock, I got 17-18 MPG city / 21-22 MPG hwy. A few months ago, I had MAC mufflers installed. My MPG plummeted. Now I have been experiencing 12-15 MPG city / 19 MPG hwy. Everyone says it must be my driving habits, due to the new sound I must be heavier on the pedal. I have NOT changed my driving style. To prove the point, I tried driving agressively on one tank vs driving mildly on another tank. No difference in MPG! Still 12-15 city/ 19 hwy. I brought the car to the dealership and they told me that the "Break-in period" on the engine is 10,000 miles. They stated that since I have 9,500 miles, I could expect a fluctuation in miles and that the the advertised MPG of 17 city/25 hwy is a range that could be affected by weather, gas quality, etc... They further said that unless the "check-engine light" is on, they would not find anything. Then, a tuner suggested that I try disconnecting my battery overnight to let the computer reset itself. I am a little skeptical, but am considering it. Has anyone ever experienced this? How did you remedy the situation? Would disconnecting the battery rectify this odd situation? What else could the problem be?
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jmart69x
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Try the computer trick. It's easy and it can't hurt anything.
These cars have an ECU feature that "learns" driving styles and adjusts the drive-by-wire system to suit. Many people report improved throttle response and power after doing the battery disconnect trick....
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Black 2006 GT Coupe
Dynatech LT headers & X; Borla catback
C&L CAI; 93 oct tune
Full BMR, Spohn & Steeda suspension
D-Specs; Alum driveshaft
Second Skin Audio damping; Infinity spkrs;
Goodyear Eagle F1 255F/295R - FR500 wheels
Try the computer trick. It's easy and it can't hurt anything.
These cars have an ECU feature that "learns" driving styles and adjusts the drive-by-wire system to suit. Many people report improved throttle response and power after doing the battery disconnect trick....
Yeah definatelt try diconnecting the batter, I have also heard that it has helped people. Those numbers are low becasue I get about 21-23mpg and drive her hard a few times a week.
I have a 2006 Mustang GT 5-speed. Fully stock, I got 17-18 MPG city / 21-22 MPG hwy. A few months ago, I had MAC mufflers installed. My MPG plummeted. Now I have been experiencing 12-15 MPG city / 19 MPG hwy. Everyone says it must be my driving habits, due to the new sound I must be heavier on the pedal. I have NOT changed my driving style. To prove the point, I tried driving agressively on one tank vs driving mildly on another tank. No difference in MPG! Still 12-15 city/ 19 hwy. I brought the car to the dealership and they told me that the "Break-in period" on the engine is 10,000 miles. They stated that since I have 9,500 miles, I could expect a fluctuation in miles and that the the advertised MPG of 17 city/25 hwy is a range that could be affected by weather, gas quality, etc... They further said that unless the "check-engine light" is on, they would not find anything. Then, a tuner suggested that I try disconnecting my battery overnight to let the computer reset itself. I am a little skeptical, but am considering it. Has anyone ever experienced this? How did you remedy the situation? Would disconnecting the battery rectify this odd situation? What else could the problem be?
Are you measuring your gas mileage or just going by the computer? To get 12 mpg while driving easy would require a very rich a/f ratio, which you would think would set off a check engine light. If 12 mpg is your actual measured fuel mileage on a full tank of gas to empty, then I'd be looking for a fuel leak. Does the engine start easily?
I have been measuring my MPG by resetting the trip info meter each time I gas the car up. Have not noticed any fuel leaks. Car starts up no problem. Dealership supposedly did a diagnostic and confirmed that the car averages 14 MPG (No ****), but couldn't offer any helpful assistance- total waste of time dealing with the dealership and their attitude. I will try disconnecting the battery. I'll keep you all posted on my progress.
with my 06 gt stock except flow masters i was getting around 14 city and 24 hwy. after all the mods including gears i get around 12 city and 21 hwy. i am quite heavy footed also. your in town mpg at 12-15 seems normal. your hwy at 19 mpg seems low.
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2006 GT
Boy Racer Body Kit
Cervini C-Series Hood w/ Roush Scoop
Steeda CAI w/ Pro Flow Elbow
SCT 93 Octane Tune
Steeda Throttle Spacer Plate
Steeda UDP
4.30 Gears
SLP Loudmouth Exhaust
Black Panther 330 20x9 Wheels
Nitto 275/35/20
In order to measure the proper MPG on the highway, you must make a fairly long freeway run. With a full tank of gas, not topped off, which means you don't fill it to the brim just before it overflows, drive 100-200 milesnon-stop on the freeway and refill it using the same method. Using the same pump and station would be great but not always convienant. That's how you get the best estimate of your fuel consumption.
Compare against your cars computer and you will see if there is a difference.
I know when I fill mine up there is always a slight difference in how much fuel the computer says I used and how much I get at the pump.
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Motor Built and tuned by ST Motorsports
"Moddadiction," I'm looking for a 12 step program . . .
Poor Gas Mileage - 2006 Mustang GT
