Just filled up my tank (had 1/4 already) so i put in $56 worth of 93 octane which comes out to a little more than 14 gallons. As you can see the meter is over the F. I never really mess with the dash buttons but recently ive seen it say like 13.9 MPG, never thought anything of it until recently when i was looking up the average MPG that other people get (yes i did look into the MPG before i bought the car and i know that its known for 19 city/25 highway). So i invested in some fuel injection cleaner which should be here in a few days.

ok well my point is i have over a full tank and my dash currently says 12.9 MPG and 234 miles until empty. WTF?! My cars got the stock 17's, NO after market parts not even an air filter, has the premium, nav and tech package if any of that matters.

Anyone know whats going on here?

 

It's probably close if you've been doing city stop-n-go driving. When you plan on doing a road trip reset your dash meters and see how it goes. I typically got 15-18 city but up to 28 hwy.

Drive the hwy for a few miles, reset the meter, continue driving the hwy and you'll see a much higher number.

 

how many miles are on your car, how is the maintenance (are you keeping up with it). What is your driving conditions like. Are you a lead foot or do you baby the accelerator.

 

Honestly both, im not that hard on the pedal most of the time.. i forgot to mention i used to see like 333 miles "till empty" on the dash board when i used to fill the tank up. I dont get it? How often does the MPG # on the dash change?

 

Your in New York, if you don't get the car out on the highway,, that might be all your gonna get, you didn't say how many miles car has, and if it generally runs good, or not. like others have said, It needs to get out on the open road, ( if possible ) and then watch your real time "mpg" gauge and the digital vacuum gauge in the cluster.

 

Im at about 92k now.. at 80k i had infiniti do the 15k maintenance (stuck it up my @$$) changed air filter, cabin filter, all that ish. I have the oil changed every 3k miles, non synthetic high mileage oil. I got the car at 78k and didnt know if the previous owners used full synthetic so i figured id do with non synthetic

 

You may need to put in on the highway and run it hard for a few miles.

 

Youngdip, rather than worry about potential issues with your car, I think you would do well to educate yourself about the functions of your car. Based on your comments so far, you could benefit a lot from simply reading the owner's manual. (btw, they're even available for free if you don't have one)

It could well be that there is absolutely nothing wrong with your car; just with your ability to understand what it's systems/functions are telling you.

 

I remember for i had the Supercharger on my car i would average between 23-26 MPG ( that is babying the car). Now that i am SC, i get 17mpg. Once i got 23 which i don't know how i did that. I say reset your ECU and have it relearn your driving habits. Maybe drive until you see the gas light come on and see if your mileage comes out better when you do the math for your MPG. I am pretty it will be pretty close but the calculated will give it to the exact point.

 

That 'miles til empty' computer is very reactive to how you drove just before you fill up.

 

If I grandpa G35 in city traffic I get 13.5L/100km so like 17.5 MPG...

Normal driving I would say about 15.5 MPG is what I get in the city.
On the hwy the best I have ever got is 24.7 MPG doing 60 mph for 3 hours.

Most of the time if I am just cruising above 70 mph and not moving around that much its at 23.5 MPG.

The rear brakes tend to dry up quickly. Do you have an abnormally hot wheel or rotor? Could be dragging a brake caliper.

 

I hope not but i will listen and look into it

 

O2 sensors. When they go bad your mileage dips wayyy low. Sometimes by half if its bad enough. Its most likely an issue of not functioning to its full extent rather than being just straight broken, so you won't necessarily throw a code.

 

Our cars learn the past, how we drive before you fill your gas. Let's say you were driving city before you fill up the gas, try to drive the car to the freeway and you can see that MILES BEFORE EMPTY will go up. I noticed this before when I did my road trip with my car. I filled up my tank day before my road trip it says 230 miles before empty. Then driving from LA - Nevada - Utah - Arizona I noticed everytime i get gas it goes up to 300+ miles before empty. So our car adjust how we drive them (guesstimate)

 

I wanted to know if he tried the ECU reset? Haven't heard anything yet.