Granny Oakley

In 2002 I purchased a new 2002 Honda Civic EX with a manual transmission. It got 30-31mpg in the city and 43-44mpg on the highway. I traded it in this spring for a 2015 Honda Civic EX with a manual transmission. It now has about 3400 miles on it so it should be broken in by now. However, I am getting only about 23.8mpg and not the 28-30mpg advertised. I do not drive this car any different than I did the other one. Should add that I am female, and use the car to go to and from work, to the grocery store and occasional trips out of town to visit the grand kids.
Why the BIG difference in gas mileage? Does any one else with a 2015 Civic EX, manual get such crappy mileage? Is there anything I can do to improve the mileage other than buying a different car?

ezone

It's a bigger car all around than your old car. Bigger body, less aerodynamic (IMO) and heavier. IMO it's sometimes amazing they do get decent mileage in spite of those disadvantages.

A quick look on https://www.fueleconomy.gov shows 28/36 for a manual trans 02 Civic (link)....and strangely enough the site shows the exact same for a 15 Civic with manual trans (link) too.
(Note the mileage rating on the older car has been 'corrected' according to the linked site. See the bottom of this post.)


Some common fuel Economy killers:
Short trips
Accelerating too rapidly
Accelerating too slowly
low tire pressures
winter blend fuel (nationwide)
Cold weather
long warm ups
extended idle time
low quality fuel
Ethanol in the fuel
Speeds above 55MPH

And lastly, the methods the EPA uses to calculate fuel economy changed from 2007-2008 or so, all cars went down a significant amount even though nothing mechanical changed in the cars, they were exactly the same as the previous years cars.
The ORIGINAL rating on your car was higher than the above quote....it was probably rated at 33/39 back before the change.
Link: https://www.fueleconomy.gov/feg/comparempg.shtml#id=17554

ezone

What method are you using to determine your gas mileage?

Are you calculating by hand with each tank fill up?
Are you going by the display in the dash?

How is that display set up?

You have the options to make it reset the trip meter (and thus the gas calculated mileage) for each of two trip displays A and B:

Manual reset
Reset with tank fill
Reset with ignition off