I would think anything below a 15 in city driving is very low. My car gets around 17.6 mpg and I floor it pretty hard in the city and don't even try to save gas.

If you're getting that low in mpg, maybe people are using lower octane rating gas or lower quality gas. I use Mobil/Exxon 93 always.

 

We don't have 93 octane 'round these parts.

 

oh highway i get about 21-22 mpg..city...17...feel like i drive a mack truck....

only seem to get 280 a tank..blows

but i use 89 pct now

 

in my 2008 im averaging 24.1

 

Woah.. 24.1 according to the dash screen that averages out all the miles driven from day one, or according to the center dash screen that you can reset between fill ups?

I'm going by the non resettable figures on the dash... mine is 18.3 since the beginning.

 

I have a 100 mile commute, drive conservatively at most times, and like a teenager at others. My average about 26.5 per tank. Some times I get 23.5 to 24. I am usually driving at 80 mph for these tanks. Right now, I am at 27.5 with the cruise at 65 mph for the duration of the highway portion and I will fill up tomorrow.

 

I do a good mix of driving. Around town I usually put in 16 gallons at 300 miles. On the freeway 100% (like a trip) I can get 350 miles on the same 16 gallons. I have a problem with my throttle though. Only seems to have an on and off! Nothing in between.

 

What do you mean 'non re-settable'.
To reset the one between the gauges, press and hold the button with the white dot.

I reset both of mine all the time.

 

is the X really that much worse than RWD only? I know it's suppose to only be a few MPG..but still much better than what i am getting

 

I drive an X and my mpg is 17.6 in the city...it's not really that much worse than RWD.

 

08 sedan RWD here, i average about 20mpg per tank

 

No it is not.
I owned the 07x (4 years) before the 6MT. Every once in a while I manually track the mileage for a couple weeks on Fuelly dot Com. The only time I have seen a small difference is with highway driving. About 1mpg based on my calculations.
It all depends on how we maintain and drive them.

 

I always get 27.2 at 71 mph turnpike, could do better if I slow down, ha ha

 

2007 G35X with 70k miles, and I have averaged 18.1 over the last 5k miles with a mix of city, highway, and back roads. I usually average low 20s highway and can get 24-25 pretty easily going a steady 65 occasionally passing. Best ever was 25.6 on a longer drive.

City seems stuck down at 14-15 no matter how I drive. Going to clean MAFs since idle is craptastic lately and see if that helps.

Back roads with a few stop signs, lots of curves, and some hills gets me 21-22 pretty consistently driving 35-55.

 

I tracked and logged my miles per gallon for nearly a year using the miles travel divided by gallons at fill up method. I logged both 89 and 93 octane gas (what is available in my area) and summer blend. I drive about 75% highway, 25% city and drive fairly spirited.

I found that I would average about 18 mpg in the winter and about 19 mpg in the summer, depending on whether I used 89 or 93 octane gas. The 93 was good for about a 1 mpg improvement.