Just got my g35x the other day with a full tank of gas from the dealer
i've driven it about 120 miles and it's already half way done with the tank
being that its 20 gallon tank, that's about 12 miles per gallon
i know that the gas economy is pretty bad on the g35x but 12 mpg is pathetic
40% highway driving and 60% city
so far i've limited my AC use
is this because of the way i'm driving the vehicle (i.e.-under 4000 rpm) during the break-in period?
after the engine is broken in, will the mpg get better?
basically, is this abnormal?
any help will be appreciated.

 

Let it break in....that's no better than what I got ....and still do whenever I re-set the ECU after performance up-grades....lol. Mine is very sensitive to a heavy foot, but then again I would'a bought a Camry if I wanted a mundane family sedan. Hang in there, it'll get better with time. Most guys here get good (if not a little exagerated) mileage and I'm sure you'll be just fine

 

My first fill up was shy of 15mpg. The car has almost 4,000 miles in it now and my average mpg is right under 17. The best I've had one time was 19.99 mpg and that was mostly highway driving. Have yet to break 20. Maybe highway driving plus ac off in the winter might accomplish that.

 

I have 2300 miles on my 05 and I drive like a total a$$hole. I average around 15-17mpg

 

We have a little over 6000 miles on our '04 and we average about 19 mpg. I am in the middle of some gas experiments right now so it is a little hard to gauge since the AC is fully wound up. The best I have ever gotten was on a trip in May I got right at 25 mpg. I know the X is a little less efficent that the reg sedan but it should come up after you get it broken in and it adjusts to your driving style.

 

You're making mileage calculations based on guesses. You don't know if the tank was "full" from the dealer or just showing full on the gas guage. It could have been as much as a gallon less than full. Also, you guess that the guage at half full means you've used 10 gallons. Your guage may show half full when 12 gallons remain in the tank. (My G35x usually has 2 gallons left in the tank when the low fuel indicator light comes on.)

Try a more scientific approach to calculating gas mileage. Fill the tank, set a trip odometer to zero. Drive and when you fill up (you'll have to fill the tank just as you did previously) divide the miles on the trip odometer by the number of gallons added. Do this three or four times and you'll start to get an idea of your actual fuel economy. Don't forget to reset your trip odometer with each fill up.

 

LMAO! Nothing like telling it like it is!

No X here, but get between 18 - 22 in my normal day to day, and have hit 26 on the highway.

 

....Not broken in yet.
....Gauge may not be accurate.
....The dealer may not have filled the tank.(mine says full long b4 the tank is topped off.)
....Do an accurate check and then break it in.

C.

 

hi
looking to buy a new g35x

noticed here people complaingin of gas mileage

Do any of you just use 87 octane?
Ive heard better gas mileage on this and THE CAR RUNS FINE

 

Seriously, I am satisfied with the gas mileage on our G35X, I believe my gas mileage is perfectly acceptable for the package I purchased . It has only seen 91 Octane or sometimes 94 when it is available. I am getting what I expected, after all it is considered a luxury sports car and with spirited driving you cannot expect fantastic mileage figures.
Drive your car like a granny and your figures will improve or buy a 4 cylinder econo-box. Once, only once I drove granny style (Just over the speed limit on the highway with cruise on a long trip) and my mileage figures were pretty close to the figures published in the Infiniti brochure. But that was no fun.
OR enjoy your car and have fun and don't fret about your gas consumption

Hmmmmm , I wonder if they will ever have a G45X Yesss raw V8 power

 

Gas mileage is pretty bad using it on the city. Use the highways (no traffic) and you will get better results.

Drive long straights with cruise control and you can get over 25mpg!

 

I have a 04, 6mt with about 6k on it and my overall average is about 22 mpg. I topped out at 28.5 on a highway trop last month. mileage varies a lot based on city vs highway AND how heavy your foot is. good luck.

 

Let it break in, it should average about 17-19 MPG.

 

I thought I was in the same boat as the original poster. I bought 05 G35X about 3 weeks ago, had 6 miles on it. The dealer filled it up with crappy 87 octane - thought they were being nice. I have the nav system, so it calculates the average fuel mileage for you and saves the last 15 tanks or so in a chart form to let you see your fuel average (for those of you without the nav). Anyway, the first tank was about 17 mpg average. Second with 93 octane was around 18.5. Both of these are with never driving above 4000 rpm and not above 75 mph on freeway - probably 30% highway, 70% city. I went on a 700 mile round trip to chicago this last weekend. Averaged 22 mpg first tank and 22.8 mpg second tank on the trip. The cruise was set at 81 mph on the second tank for the ride home, car was about 3200 rpms at this speed. I am pretty pleased with that. I wish this cars 5th gear was about 700 rpms lower through. At 75 mph, the car is at 3000 rpm, the Infiniti I35 is at 2500 rpms, and that is with a 4 speed auto trans! If our 5 speed auto had a lower overdrive gear, this car would get much better mileage, but alas - I am still happy with around 23 mpg cruising at 80 mph with the X. It will only get better as the engine breaks in - only have about 1200 on it now. Man I am glad I got the clear bra - the front end was COVERED in bugs that I just cleaned off.

 

I use my Nav display info for MPG. I'm assuming that the info it is giving me is accurate.

The best I've done was 26.2 MPG on a 175 mile trip, flat terrain, no a/c and 65 miles per hour.

The worst 15 MPG all around town.

Averaging 20-22 MPG with a mix of 50% city 50% HWY