I just got a 03' 5AT g35coupe few months ago.. everything seems okay. However, one full tank of gas can only go about 400km. Can someone please tell me how if this is normal for my car? or There are some major well known solution that can get this fixed. Please help me out.

 

no one knows??

 

Definitely not normal. You should be getting about 15mpg.

Sadly, once your car gets crappy mileage, it will continue to get it. There is no fix other than a tune up.

Check your intake filter, spark plugs, and make sure you run Premium Fuel.

If you have the time, you should try to run seafoam in the tank and crankcase.

Then change oil and see what happens.

 

thank you for your kind reply, a tune up is definitely a must for me, a 80miles less per tank is just too abnormal. im running premium fuel already, but intaje and spark plugs would affect a car's performance by that much?
anyhow i just hope its not any electronical problem.

 

Honestly 250 miles per tank sounds about right. I get about 220, 250 if I'm lucky. Do some regular maintenance but if it doesn't go up at all I wouldn't be worried. You bought the wrong car if you worry about MPG that much.

 

I'm at 225-250 when I get down to 1/4 tank. Thats normally when I fill up. If i'm doing solid HWY driving I average 200 by half way. Best MPG I got was 28.75 but that was before I swapped the rear differential gearing.