i bought a beautiful black 2009 G37 coupe about three weeks ago. I tested everything(or I thought I did) and the car felt smooth and nice to drive. All it had was a few cosmetic issues but I didn't care too much cause it could be fixed over time and it was a reasonable price. Three weeks in and im noticing horrible gas mileage. I have been having to fill her up every 7 days. I started tracking my miles and it used up half the tank in 86 miles (wtf...) The guy told me he had changed the oil recently and I believed him, but just in case im gonna change the oil and get the injectors/spark plugs checked and maybe replaced. Any suggestions guys? What other approach could I take to attack this problem?

P.S. I live in Miami. The traffic here is horrible, there is a lot of stop and go just about anywhere in this city, but my friends have Gs and they don't have any problems.

Thanks in advance!

 

check your tires. make sure they have plenty of tread and are to the proper pressure.
also do all your maintenance like trans fluid drain and fill. check brakes make sure none of them are sticking. check air filter. maybe bad O2 sensor. but check for codes if any.

 

I replaced my brake pads and had the whole brakes checked, I changed the air filters about a week ago and I also had it scanned for codes. I might replace all my fluids though just for maintenance cause I dont know what the previous owner had/hadnt done

 

Post your actual miles per gallon. How do you drive it and under what conditions?

 

I get 13.5 mpg. Driven well.

 

8-10mpg
Where I live the traffic is insane... there is a lot of stopping, slowing down, accelerating, ect.. except at night. During night time it's mostly clear and I drive my car like a sports car, im always going as fast as I feel safe (I drive aggressively)

right now Ive traveled 100.7 miles since I last filled the tank on friday and my mpg on the screen is displaying 10.7 mpg with 12.4 mph and and 51 miles untill empty.

 

Hows traffic in your area?

 

Have you checked if the vehicle is stock and no modifications were done? Taken it to the dealer? Reset the ecu?

 

yes it's stock and I reset the ECU when I unplugged the negative terminal of the battery to clean the throttle body. I haven't taken it to the dealer though...

 

I'm not sure then, but I think you should get a thorough inspection from your dealer or a professional shop. 8-10mpg sounds a bit too high even for severe stop and go traffic. Where I live, I get a little under 18mpg with little to no traffic driving aggressively. Is your idle a little high?

 

I average 15 mpg..

 

average over 10 fills : 19 mpg in city traffic
g37x coupe

 

Same, City traffic with G37x Sedan. I'm in heavy traffic as well for 50 of my 60 mile commute

 

Sounds like most of the issue is how you drive and traffic conditions. Also you cannot rely on the computer to give completely accurate MPG. Figure it accurately yourself over an entire tank. Or several tanks. Then drive in a different way if gas mileage concerns you.

 

Sitting in bumper to bumper traffic is not going to give you decent MPG

Leave Miami on I95 in the middle of the night with light traffic, drive to the Ga.Fl border and you'll see quite different MPG results.




These are the results of my last round trip from NJ to Lake Worth, Fl.

Four fill-ups on the way down, two fill-ups while in Florida with local driving, and four fill-ups on the return to NJ.

Actual math calculations for the ten fill-ups. Miles driven/gallons to fill-up

24.49, 26.79, 24.9, 26.5, 15.9, 15.42, 24.26, 24.54, 24.05, 25.94

My G has never seen a drop of premium


All regular all the time








Telcoman