I just purchased a 2009 g37 x coupe and I am only getting 8.9 mpg city. I use 93 gas all of the time but nothing changes, I changed all six of the spark plugs. I even added STP fuel injector cleaner in the gas but not much improvements. Can someone please help me out with some advise with my situation and what I can do to get better mpg. Thank you!

Welcome to NICO!

What is your driving cycle like? under 10MPG might be normal if you're only driving like 5-10 miles with a long warm-up cycle.

Ultimately, the true test is to get the car out on the highway. Take it on a 30+ mile blast on the highway and see what your MPG is that way. If it's normal (25+), then you know the car is performing properly.

@ elwesso I will try that tomorrow when the rain clears up .thank you and I drive less that 8 miles per day

Are you basing the mpg number from the navigation screen or are you filling up the tank and dividing the miles driven per the gallons used?

I look at the dash behind the steering wheel

That's right, it shows the mpg on the dash in your car. Sorry.

I'd suggest filling the tank and see how many miles you get on that tank at the next fill up and calculate the mpg manually. The display on the dash may not be accurate.

nayeem123 wrote:I just purchased a 2009 g37 x coupe and I am only getting 8.9 mpg city. I use 93 gas all of the time but nothing changes, I changed all six of the spark plugs. I even added STP fuel injector cleaner in the gas but not much improvements. Can someone please help me out with some advise with my situation and what I can do to get better mpg. Thank you!

You can get much better mileage on a road trip



On my previous 06 G35 6sp I tried a one month test of 91 and another one month test of 93 octane,
I get better mileage on 87 octane and have used it ever since.

Telcoman

Hello fellow NICO's, I just joined the band wagon due to me buying an 08 g37s. Been searching around because it seems like I am missing on average about 5 gallons when ever I fill up. Am I wrong that the tank is 20 gallons? I fill up around an 1/8th of a tank and only put in about 14ish gallons and the fuel gage says im full.. I don't want to start a new thread if this is beaten to death, I do see a lot about fueling issues and am just wondering if this is indeed the same issue or not. Thanks

The most miles I've traveled on a full tank was 385 and it took 16.004 gallons to fill up giving a 24.06 MPG The gauge was close to the empty mark but the warning light had not come on yet.
The tank holds 20 gallons.

Telcoman

The tank holds 20 but the gauge may not accurately represent how much you have left. This is true of most cars. There is usually a planned "fudge factor" built in to save those who like to run it almost dry shoe leather..

Thanks guys. Guess I just got to learn the cars quirks.

Out of the 20 gallons appx 2.5 of them are reserve, thus, the max gallons when the car hits E (or drops to 000 miles remaining) would be around 17.5.

Supposedly.

Audacious is correct the reserve is supposed to be 2.5 ....BUT in many instances it is much more and there is more gas in the tank thna the gauge shows : )

I guess that adds up then. When I fill up with the mentioned 14ish gallons my computer says a range of 40-50. So 20 mpg or so is pretty accurate with roughly 2 gallons left. ..... that is if the computer does not count for the reserve portion. Think I will start a new thread about my particular maintenance questions. Thanks guys, I was going to ask what the reserve tank holds also.