My mpg has always been lower than the EPA estimated fuel economy 17/25, averaging about 13 ~15 mpg. My driving is 90% city with loads of stop signs, so didn't really complain about this. The average was simply calculated by distance/fuel burned. The same result was displayed on the average fuel consumption screen.

For the last two tanks, I have been experiencing a sudden, dramatic drop of mpg averaging around 7 to 9. I haven't changed my driving style, no accidents to report, no modification to the vehicle that would affect the fuel consumption.

I already contacted the dealership and scheduled to bring the car in next week.
Searching the forum gave me this:
https://g35driver.com/forums/g35-sed...-much-gas.html

but the OP was retarded and the thread was useless.

Another think I realized after searching through this forum is that my tank never holds gas beyond 15 gallons (I believed our cars had 16 gallon capacity until I found this). This thread
https://g35driver.com/forums/g35-sed...-readings.html
kind of explained the situation, but the dealer said they will check that issue as well.

anyways, just wanted to share this since it sucks to have a vehicle with 8 mpg while living in a state where gas costs like gold.

 

Hi guys,

Brought my car into service this morning. Dealer said they'll check the sensors and any thing that may malfunction and affect the fuel consumption. The problem is, they'll need to fill up the tank and drive it a few times, which means I won't be getting my car back for a few days.

Well, I'll post for any new info.

 

Check ur air filters. If its dirty replacing it can give u 3-4mpg extra per gallon

 

thanks for the reply redbaron, but my vehicle is currently at the dealership. I recently replaced my air filter do shouldnt be a problem, but if it is the dealer should fix that.

 

Gas tank capacity is 20 gallons total which 2 gallons are used as reserve. Usually when the car indicates low fuel and distance to empty, it means you are most likely goin to still have 2 gallons.

Now, that has been the factory setting for our G's. From my years of observation of MPG, I found out the gas read out also changes depending on your driving habits. Many have witnessed that the gas reads empty only after the first 16 gallons of usage and so have I, but tr truth is that there are still gallons of fuel in the tank. I have experimented by filling up the tank upto 20.xx gallons (car died of fuel starvation right as I was pulling in the gas station. lol) and several other times where I have topped off 19.xx gallons of gas. It's a bit awkward how the Infiniti calculates the remaining gasoline in the tanks, but you should still know that you have 20 gallons of gas.

Also, there is a TSB for many of us who weren't able to fill the gas completely. Usually with this symptom, you can only fill up about half tank before the valve at the station kicks the lever out. This can be easily fixed at a local Infiniti dealership.

 

Thanks BLUESLATE for your info, I saw similar posts in the thread listed above (some say 3 gallons of gas in reserve, others say 2), so when calculating my gas mileage I ignored the fuel gauge and simply used what ever gas I put in (in most case 14 gal). Still to hear from the dealership what the issue is.

 

Let us know when you find out what the problem is.

 

Yea, I would love to know, because seem like my gas mileage has decreased as well. I think I might need to get my "induction" cleaned that's what the dealer told me..

 

From my personal experience, when the gas light comes on there are approx 4 gallons left in our 20 gallon tank. Nissan does this in hopes that people will get gas right away as to not burn up the fuel pump. The gas in your tank is the only way to cool the fuel pump as it cycles on and off at a high rate of speed.

 

Hi guys, just picked me car up from service. The following was the explanation given by dealership.

Gas gauge malfunction resulted in misreading the amount of gas consumed/available. The system is all connected, and when the gauge is off, the warning light will also turn on even with sufficient amount of gas. Checked the O2 sensor but was functional. Fixed the gauge (and other components associated with reading) and re-filled the tank, now gives approximately 210 miles for distance until empty.

After picking my vehicle up I drove around for about an hr and the issue seems to be fixed (cannot tell what the fuel consumption is, but an hour of driving would have killed 1/4 my gas before the fix). Dealer said to contact them if problem persists.

Will update this in about a week. Thanks!

 

Hi guys, just picked me car up from service. The following was the explanation given by dealership.

Gas gauge malfunction resulted in misreading the amount of gas consumed/available. The system is all connected, and when the gauge is off, the warning light will also turn on even with sufficient amount of gas. Checked the O2 sensor but was functional. Fixed the gauge (and other components associated with reading) and re-filled the tank, now gives approximately 210 miles for distance until empty.

After picking my vehicle up I drove around for about an hr and the issue seems to be fixed (cannot tell what the fuel consumption is, but an hour of driving would have killed 1/4 my gas before the fix). Dealer said to contact them if problem persists.

Will update this in about a week. Thanks!