So I recently just started paying attention to how many miles I have left before empty. Everytime I fill my tank up I get a different mileage. I've filled up & had 248 miles before E, another time it was 315 before E, etc.

Does anybody know the true mileage before E on a full tank or why I'm getting a different mileage everytime?

 

You're getting different readings because the computer in the car is calculating how much gas, and your driving style.

So perhaps one week you were in a rush to work a few days. You might have had to step on it a few more times etc. So the computer would consider your aggressive driving style and the amount of gas. Giving you the 250 something MPG's.

And then after the initial fill up, you spend the next week taking it easy. Maybe you spent more time on the highway this week and less in the city? So his next time you fill up, the computer again considers your granny style of driving and the gas added. Giving you a much higher MPG.

The answer you're looking for isn't going to be a set number. More of an average. So it really all depends on many variables.

Hope this helps!

 

Over the last 30,000 miles I'm averaging 23mpg. I can consistently get 400 miles per tank. My daily commute is 100 miles of 80mph highway...

 

I range between 320 miles and 450 miles depending on all stop-n-go traffic or all highway cruising.

When you alert goes to --- then you have about 1.5 usable gallons left.

 

True dat. I just ran mine down to the triple ---. Drove for about a day on that. People dont realize there is about a gallon or a gallon and a half reserve. Our max does have the potential to hit 600 miles per tank if driven low rpmd and on the freeway. But...yeah l none of us will ever see that. I get about 375 per tank and i drive mostly city.

 

I average 350 mpg to 380 mpg. Some days I drive normal and some days I punch it.

 

Wow... I could get by putting in only couple of gallons a month if I got that many miles on a gallon of gas...

 

I never go less than 420 miles between fill ups, and rarely put in more than 16 - 17 gallons.

 

 

I do mostly city driving and rarely punch it over 3,000rpm. I'm lucky if I see 300 miles before the light comes on. I usually fill up before the "Distance to Empty" goes to "---" though so I would assume I'd get another 50 or so miles if I did let it run down to "---". Nitehawk, how are you getting 375 miles a tank in the city?!?

 

Normal driving to and from work and around Little Rock in my 2012 with 91+oct I can get 300-400 miles per tank. I recently took a 4000 mi road trip over 10 days and would often seen 500-580 "distance to empty" when filling as I would be getting 26-29 mpg. One tank I did crack the 600 mark when I was driving for about 200 miles with cruise set to 68 mph with no wind...but some terrain (driving from Salt Lake City to I-70 on US6/191). The readout when I filled up was "distance to empty: 605 miles" which worked out to over 30 mpg that lone tank. The average for the entire 4000 mi trip was right at 26 mpg hand calculated. That did include a lot of terrain and 75-80 mph speed limit areas.

 

I have cxj spacers kit and k&n filter. I rarely go over 2000 - 2500 rpm and ive noticed that you can get up to speed a few seconds longer but accelerating i watch my gauge like a hawk (no pun intended lol). You dont need much power to get the Max moving. I can get 2 weeks out of her driving like this. Now, there are days and times that do permit me going faster (i.e. silver sti yesterday that passed me @110mph on the 215). I almost put my foot down and showed you what the max has, lol, almost got me. :-D. No freal though i just hate filling up every week when i drive "spirited". So i alternate tank fulls. This tank im driving like a grandma, next tank will be a gta5 war machine through the streets. :-) My reward hehe

 

I drive 95% highway 70-80mph. 80 miles a day. Usually seeing 400+ miles to the tank with cheap 87 octane. Trip computer says I am getting 25-26MPG.

I had a 2014 3.5 Altima SL for a year (got rid of it in October...SOOOOO many problems)...it got 31MPH with the same exact drive.

I knew it would be less and that it's "rated" 26 highway...so I'm happy. It was nice getting 31 before though.

 

The most I was ever able to put in the tank was 19 gallons. The tank holds 20 and when I finally stopped for gas, the needle was on E and the car indicated "--" miles to empty.

To answer OP's question: the computer is guesstimating distance to empty based on driving style and MPG data. It will continue to guesstimate throughout the tank. It's more about being safe, as running out of gas can burn out the fuel pump.

The few times I just haven't had time to fill up and pushed it, I've gotten right around 400 miles before stopping. Most of the time though, I try and stop and get gas when I hit 1/4 tank or so, or around 325-375 miles of mixed driving. On long trips of mostly highway cruising, I can go further without stopping.

Don't trust the computer. It's optimistic on actual MPG's because it is constantly compensating based on driving style. My last tank was a lot of idling in traffic and city driving. The computer said I was averaging 20.4 mpg when I stopped for gas. My Road Trip LE app on my iphone (which is free, btw) tracked me at 18.63.

Over the last 10,286 miles of mixed driving (I started tracking the car on March 28, 2014), I'm averaging 20.9 MPG. I used 507 gallons of fuel at an average cost of $3.889 and a fuel cost per mile of $0.186.

 

Damn, love the stats.

I just reset my trip computer today so I'll see how much it estimates my MPG at over the course of the next week. I have about half a tank of gas left so I'm hoping it takes me to 200 miles before I have to fill up.

 

We should keep in mind that 'miles per tankful' is sort of a meaningless number, in that it is not related with fuel efficiency. Fuel efficiency is MPG, pure and simple.

The guages and indicators encourage us to fill up before running the tank low because the fuel pump is located inside the gas tank and depends on being immersed in gasoline in order to avoid overheating. Replacing a fuel pump is fairly expensive.

Also, if we allow the tank to reach empty, there is a realistic chance we will damage the catalytic converter to the point it will not pass any emission check. A new catalytic converter installed can range from around $350 to $1000 depending on where and who replaces it.

But my primary reason for never letting the tank drop below five gallons is because, in 65 years of driving, I have encountered many situations where a power outage kept gas pumps from being operational, and I would not have enough fuel to reach the next town (I spent many years in the southwest, where storms can be brutal, repairs can be slow, and towns can be far apart).

Also, in emergency situations, I don't want to have to find a gas station and fill up on the way to the emergency room. But that is just me. I understand young folks love living on the edge.

 

For those who like stats, this is every drop of gas that has been in my car since 9/3/2012. 91 octane (utah's premium), best guess is a 50/50 split of highway and city driving.

 

This is a blessing for a stats major such as myself. What app is this?

 

I use iOS, and the app is called Gas Cubby. There are plenty of decent fuel log apps. This one was great a couple years ago, but just ok now. Developer support has kinda ended, although the app is still working fine. Lots of options though for similar apps. Easy to use and interesting info.
http://Gas Cubby - Fuel Economy & Se....re/us/0IYOr.i

 

I'm running on Android

I just installed the FuelLog - Car Management app and will be using it starting with my next fill up.

 

Very good points, as usual. Always enjoy reading your feedback and appreciate your insight. So much easier and cheaper to just keep the tank above 1/4 at all times than deal with the potential consequences.

 

I took a 310 mile road trip yesterday after filling up with 92 octane Chevron gas. At the end of the trip I filled up again taking 10.7 gallons. 28.9 MPG.
Sustained minimum speed 55 and max 65.
Car has 41,000 miles.
RSA's at 35 PSI.
No performance mods.
One passenger in car.
Wx was 50 degrees with showers.
Oil used Castrol syn blend.

If I traveled long enough to use 19 of the 20 gallon tank capacity I could have gone about 550 miles on the tank.

 

Thanks for the info!! It was racking my brain trying to figure out why the mileage was changing each time I filled up. I figured it was due to how low the gas tank actually was.