I have a 2010 Ford Taurus. It has a mileage left to empty estimate. Normally the mileage to zero is greater than 400 miles immediately after a fill-up but has recently declined to around 360 miles. Does this indicate a need for tune-up? or should I look at something else?
Re. “tune up” have you done the services listed in the Owner’s Manual for the age and mileage of you car?
No driveability issues?
Check tire pressure; check for a dragging brake (one wheel hotter than the others).
I would go no further until you make a direct measurement of the mpg’s, e.g. miles driven divided by amount of fuel put in the tank.
Do that for at least a couple of fillups to get an average.
I can’t see your odometer from here, Judy. Can you park the car a bit closer to the computer?
In all seriousness, as Circuitsmith implied, you need to make sure that you have done all of the required maintenance, in terms of both odometer mileage and elapsed time.
If you have gone beyond the specified odometer mileage for replacement of the spark plugs and/or the air filter, then–yes–this probably means that your gas mileage would improve after you take care of the skipped maintenance. As was also mentioned, making sure that your tires are inflated properly can also aid in getting maximum gas mileage.
Some other things to check include the possibility that you are carrying around more in the car’s trunk than you used to. For example, people who store extra tires and wheels in the trunk will suffer a drop in mpg due to the added weight. I knew one guy who just never seemed to get around to taking a few hundred lbs. of newspapers to the recycling center, and he chauffeured that weight around in his trunk for a few months, while wondering about why his gas mileage had dropped.
Also–Is it possible that your driving patterns have changed?
Are you doing more local, short-trip driving now? If you are, that would definitely take a toll on your gas mileage.
I am always amazed how many people contact this forum about fuel mileage concerns and don’t know what Miles per Gallon they are actually getting. So many things can effect mileage they don’t even consider: ( different driving patterns-different fuel station or even a different pump-traffic causing more idling )
I don’t even pay attention to the miles to empty readout after refueling because after a few miles on the highway it changes.
On another forum one person was obsessed with how many miles he drove before refueling and wanted advice on how to increase his distance. No one could convince them that their MPG was more important and they had no idea of their fuel mileage.
Typically the miles-until-empty calculation is based on the type of driving done most recently, so you’re reading too much into it. As others have said, measure your actual fuel economy, preferably over a few tanks.