So my gas mileage on the home screen when I hit status said 16.2 mpg... But when I just filled up and calculated it using my trip mileage divided by the number of gallons it came out to 15.6... I imagine the trip/gallons is more accurate, but why such a difference? Whenever I do it in my dad's Jeep, my calculation and the car's MPG is just about the same, maybe .1 off. BTW, I have no Navi...

 

Is your car new? That might skew the numbers slightly.

However, as a software engineer, I can tell you that the MPG your screen gives you is most likely a guestimate based upon engine use etc...

 

I just surpassed 4,100 miles... So it's not really new... My mileage has definitely gone up 1-2 MPG since I first got her... Was averaging around 13.5-14.5 previously

 

That mileage sounds pretty bad . Are you an aggressive driver or one who like to accelerate fast?

As for the display readout, that's actually pretty accurate in my book. I've seen them differ up to 4-5 mpg, usually reading more optimistic than the actual calculated method.

 

I religiously reset the MPG on the car every fill-up. I also use an app on my android phone that calculates to the thousandths by entering the exact amount I paid, cost per gallon, odometer reading, and gallons (to the thousanths).

I do both at the same time at the gas station and are nearly dead accurate. The biggest discrepency I have had was .1-.2

Surprisingly accurate.

 

compared to your Dad's car, there may be a difference in the period of time that is used to calculate the mpg. The Infiniti may be more than a tank maybe? I'm just guessing

PS. I've been consistently around 20mpg overall since I bought mine

 

I do a lot of city driving and I haven't reset my MPG gauge in a while. I average about 15.3MPG with very limited highway miles. To answer your question though, it's been pretty accurate. I use to reset my gauge often after every fill up as well and when I calculated the miles per gallon rate the car's calculation was pretty much dead nuts.

 

Mine is off a little. Like .5 mpg, and it's normally a little less than calculated surprisingly. Once you take into account pump tolerances and the like, it's as accurate as I am.

 

AWD kills the MPG's especially city driving.

 

To summarize, I live in NYC, sit in traffic 3-4 times a week on a highway, and do plenty of city driving... I think 16.2 is actually really good... My dad's Jeep averages around 12.5-14... And it's a V6, go figure. LOL

 

11.7MPG city driving only.. ~300 miles on it.

'11 G37xS

 

Ouch! Our cars get horrible miles in the city! I drive mostly freeway and some city, and I average 21.4 MPG right now. But that's after I got it tuned and switched to Motul Synthetic oil. Yes, it did increase gas mileage by a bit. And I don't drive very economically, either. Before the tune, averaged 20.1. After the tune, 20.9. After Motul, 21.4. Not bad, I must say. Also, maybe the K&N's had a bit to do with it.

 

One of the factors that might cause a discrepancy between the computer mpg and manually figuring it out is how you top the tank off.
Each station's fuel will cut off at different levels, depending on how they are set and how fast the fuel flows. Theoretically you could end up putting a good percentage of a gallon of gas more into your tank at one station verses another.
The only accurate way to fill up would be to keep squeezing until you see gas at the top of the gas tank neck.
This is a bad practice since some of the extra gas will flow back and eventually screw up your emission system.
A better method to manually figure your mpg is multiple fill ups, which tends to average out the fill up levels.
Tom

 

I've had her for about a week.

On my Pontiac G6, I had to fill up maybe once a month. I've already filled up once with the G37.

Granted, I've driven a bit more since getting her, and I dont think the dealership actually gave me a full tank. I think with the G37, I'll be filling up every 2-3 weeks as opposed to once a month.

It's worth it though. I'm all city driving though - lots of stop and go.

 

In New York City, you fill up your own tank, so I top it off to the nearest dollar... Yesterday, I was in New Jersey and the pump stopped at like $51.47 or some **** and he kept it there... I hate when they don't top it off... However, I paid $3.45 for premium, which is about a 50 cent difference from where I live... Usually when I top it off it is closer, considering more gas is going in (duh me) lol... And to answer everyones input on how much bad gas mileage I get, if you lived in NYC you'd understand... There's a traffic light every 1/4 mile, none of them in sequence, and the traffic is horrible... And I live in Staten Island, supposedly the quietest borough on NYC... Imagine I drove in Manhattan, my gas mileage would be about 12-13 on average... LOL