Just pulled a 300 mile trip and only spent half the tank. Theres always the chance you retarded timing by using regular fuel on a motor that needs premium. Lesser quality fuel means less mpg. Clean out your lines with bg 44k and a full tank of premium gas. Stop using cheap gas, take pride in your G, its not a beater

 

I average 80-85 mph on the freeway and get 23-24 mpg. I do floor it 2-3 times for passing each way.

 

While 13.6 is definitely too low, you shouldn't be expecting the 18-25 numbers if your're doing 80% city as as an all wheel drive G.

 

im getting roughly 240 miles to the tank , mainly all city driving, living in NY . . . 06 G35x

 

i was getting pretty bad mpg also, that's why I bought a beater.

 

I get almost 20 city and 25 highway on 89. Maybe the 6mt gets a hair better mpg?

 

mine is 6mt and i get horrible mpg. it should be measured in feet per gallon.

 

I get about 16 average...

 

It's like an epidemic. I've had mine for a year and a half. 05' 6mt w 80k miles, (N/A at the time) getting 19-20mpg 50/50-city/hwy, then after some good maintence- Seafoam, plugs, synth oil switch, TB clean, MAF clean, and more I started getting 24.0 mpg 50-city 50-hwy off chitty CA 91 pump. Calculated (not using crappy Navigation meter) mpg, usually about 350miles for 14.5 gallons. same pump at same station.

 

There's no chance timing might be pulled if using 89 octane, timing will absolutely be pulled. You have to use 91 octane, preferably without methanol.

Besides the suggestions already given have the injectors cleaned. Some people swear by seafoam, I went to a shop that hooked a machine up to the intake tube and sprayed cleaner into it as my car ran for an hr. Only cost $100 and it made a marked improvement in performance and mpg.

Since your car is awd that will effect mpg and you should disregard the mpg info coming from guys with coupes and rwd sedans, you'll never see those numbers. The tires have a big effect on mpg, all seasons weigh more than summer tires because of the different compounds and same size summer tires from different manufacturers don't weigh the same either. The same goes for wheels...less weight=less rotational mass=better mpg+more whp/wtq.

 

^^good points...also tire pressure, and of course driving style.

 

I get about 24-26MPG freeway using 89 octane.

95% of my driving is highway, so i have my tires inflated a bit more, drive using cruise control and use the A/C as little as possible. I drive about 30K miles/year. Curretly at 110K on my '06. Gonna change the plug soon.

 

Like the above posts said, use at least 91 octane. You'd get even better mileage than 24-26. I have 93 octane where I'm at, so that's the ONLY thing I use.

 

well I live in North Jersey. Mostly city traffic as well as frequent stop signs and red lights. Also Occasional trips to Manhattan. So I'm guessing its normal? I pulled a little more than you 15 mpg.


I immediately switched to 91 Octane and I swear the noise of the engine and the response of the gas pedal has been changed. Feel much better now.

I pulled 15 mpg with 87 octane/frequent stop signs and red lights.
(I did not know I had to use 91 since that was my first tank with the new car, so please dont judge me

Its AWD, 17'' Continental DWS All Season tires. I feel like its OK to pull 15 mpg under these circumstances.

As far as the other things, I'm going to give it a try for a couple more fill-ups.

Once I go on a hwy and have a long trip, I will update this post and see if I have to replace anything.

 

I once had a Saab 9-5 that I did a 2 month comparison with 87 vs the recommended 91 octane. The difference was the the 87 octane garnered me 3 mpg lower vs the 91. Doing the math it was cheaper to get more mpg with the 91 while paying for the more expensive gas. That and the engine seemed to run smoother and faster...turbo though.