I just bought my 05 G35 coupe AT with 27k and its terrible on gas. I filled up to the rim and at exactly half tank i clocked it at about 100 miles maybe a little over. I drive the car slow, i baby the thing, never floor it... That means im only getting about 10 MPG. The car is in mint condition but this gas is killing me, i 1st filled with 93 and was going to continue with it but now i may switch down to 89 and just leave it at that.

Im definitely going to take out my spare tire and next fill up try to throw the ingition cleaner in the gas tank and maybe reset my ECU...

I dont know what else to do but this is definitly not normal... Please help me, what else should i do??

 

that does seem quite bad, but when the needle is at half tank, you actually have almost 2/3 left. our gas gauges are weird.

try checking tire pressure for a start
also try calculating your mpg manually based on milage and gallons filled to get a more accurate average number

 

yeah next time i go fill up im going to calculate it exact with the number of gallons i put in. Thanks.. Anyone Else??

 

You should definitely calculate it when you refill the gas tank, doing it based on any car's gas gauge is notoriously inaccurate. I wouldn't worry about it until you prove it's actually a problem - then you might check your air filter, tire pressure, etc.

 

on the track, i got to half a tank from full in 75 miles.

 

Should i switch down to 89 gas instead of 93 my friend told me 93 burns alot faster then 89?

 

you're friend is nuts

 

Your friend has it mixed up 93 burns longer and more stable also ethanol added helps longer burns. it doesn't really matter you car has a knock sensor it will figure it out. I have been using 87 in mine 46k miles average 24 mpg mixed, no fast take offs, no need to get to the same redlight just as fast, or end up behind someone slow.

 

Ethanol decreases fuel economy, although with ethanol contents in gasoline between 5% and 10% it's not a large decrease. Ethanol has 34% less energy per unit than gasoline.

 

It can be a multitude of things that is affecting your car. When the oxygen sensor in my coupe went out, I was averaging 12 miles to the gallon driving 65 miles an hour on the highway, although this probably isn't your problem else you would have a check engine light warning. It may also be that your gas tank is giving a incorrect reading, mine does this but its never off more than maybe 2 gallons at the most. Take it into infiniti for an oil change and they will inspect the car for free, your car is still under warranty so you should take advantage of it while you can

 

And thats why ethanol is a horrible alternative also.

 

Wow do you really daily drive with 87? I've never even put a gallon of 89 in mine, I just don't see the point in saving 3 dollars every fill up, especially when our cars are designed exclusively for premium fuels

 

I have the same problem with my 04 X. I get maybe 11 mpg. Iknow its an X but i should still get getting 15 easily. I dont drive hard at all, once in a while ill get on it to hear my exhaust but thats all

 

i ran into that problem when i bought my G, 03 5AT. do a tune up.

i took a trip to SF from SLO, about a 250-275 trip, by the time i got up there. it was 1/4 left...i was like WOAH! that was when gas was $4+ a gallon on 91.

i changed the following:

1. fresh oil change
2. new air filter
just by doing that, ended up at 325+ 1/4 tank...

on my trip to LV from SLO, at 450miles..on the way home, it was a full tank + maybe less than 1/4 extra...i think it coulda done 400+ on a full tank

city driving sucks...15mpg the most
highway at 75+ average, i say 25 the most...it is a v6,

 

I did buy the car used, and yes i did get it inspected but im planning on doing a full tune on during my next oil changed which is very soon. So hopefully i should get better mileage. I usually only get about 200-250 miles to a tank, which for me being a kid sucks paying for gas, even though gas is cheap right now.