I have the 3.55 gears on mine. You'll see better mileage with the 3.31s but it'll probably only be 3 or 4 tenths better, not a drastic improvement.

 

Stock 05 GT manual - 80% highway, 20% city even though some of the highway mileage with the congestion around Baltimore, MD feels like city stop & go

Since new (5/25/2005) - 11488.2 miles / 451.57 gals = 25.441 MPG

last tank - 382.9 miles / 14.293 gals = 26.789 MPG

Seems to get the best gas mile @ 69 MPH on cruise control

 

In my almost stock 06 GT i get 26mpg but i drive on a 50mile stretch of freeway that dead empty when i go to work. When i drive around the city i get like 15-18mpg.

 

Bone stock 06 GT Manual, 3.55 gears, 1200 miles on the odo.

21.8 MPG in my daily work commute which is straight city driving, no highway. The commute is about 10 miles each way with around 10 stop lights or so. The traffic can be pretty heavy and includes a lot of time idling.

On the highway I've gotten 31 MPG at 65 MPH; 28-29 MPG at 69-70 MPH; and 26 MPG at 75 MPH.

One thing I've noticed about this car is that it takes a very large MPG hit during the warmup phase. Until the temp gage hits mid-point my MPG will slowly erode.

 

'05 GT auto here, with 93 octane tune (no CAI), getting around 16 mpg in the city and 24 mpg on the highway.

 

I've got 24000 miles on my car. I haven't reset the computer for mpg in over a year and it's slowly crept up to 18.3 mpg. I average about 20 miles a day city driving. I also make 6 to 15 1/8th mile runs on Fridays during the season.

 

05 Auto driven Hiway and City.
8147 Miles
18.5 M/Gal.
This was calculated using a Spread Sheet, counting every Tank of Gas.

 

I wonder how many of our mpg's are off due to our speedo reading incorrectly??
http://forums.bradbarnett.net/showthread.php?t=54118

 

05 GT almost 16,000 miles. i get an average of 20 to 21mpg per tank. i live in NJ soo i do sit in traffic and drive about a 60% highway and 40% city

 

My latest check was...

17 MPG city
28.4 MPG hwy (last weekend)

 

Believe it or not- 16MPG in town, 24MPG Hwy....In my GT500

 

I get 13.5 in the city 24 highway

 

Average 21mpg ,about 60% highway,40% city.2100 on odometer.
JLT2 CAI + 93 tune.
06 GT/manual
Normally cruise on highway @ 72

 

05 GT Vert with Auto
I live in a fairly rural area. Driving 11 miles to work each day - average about 21-21 mppg with a best of 23
On a long trip from Wisconsin to Denver, we averaged 24 mpg @ 75-80mph cruising speed (ok - maybe 80-85)
I run Motorcraft 5W-20 synthetic blend - I think I would do better with pure synthetic like Mobil 1 or Amsoil

 

JEALOUS!!

 

06 GT 5 speed. Mixed Hiway, local w/air on I am at 23-24 mpg. With no air I am at 27-28 mpg. That's going to and from work, normal driving. If I want to have fun than I don't care about milage.

 

i average about 22mpg in my 07 gt, mixed highway and city driving.
i have 3.31's though

 

The speedometer on virtually every vehicle manufactured reads high. This is most likely done to avoid lawsuits from drivers who get speeding tickets.

On the other hand if you check the odometer you'll most likely find that it is very accurate.

 

GT auto
14-15.5 in town depending on how much I play
23.3 highway, cruise on 77

 

16 around town & 21 on the road & 75-80
i have an auto with 3.55's