New to fuelly, need help
 

Hey everyone. Just bought a 2014 Honda civic ex. And I'm comcerned..it has 29k miles. And I've been driving it for a month now, and my odometer is reading only a 21 mpg fuel efficiency. I drive city mostly but not aggressive and I don't understand why I'm not closer to high 30s/40

Is this an issue for anyone else? Is there something I'm doing wrong?

Is this figure the calculated mpg, top up to top up, or the reading from the fuel display?
The EPA figure for city driving is only 29 mpg, so until you have an accurate calculated figure I would not get too worried.
Not driving aggressively is important, but even more so in city driving is planning ahead and avoiding situations where you have to use your brakes. Leave plenty space to the vehicles ahead so as they slow you don't have to. Or if you do, you can slow without braking. Try to avoid coming to a complete stop if at all possible. Energy to overcome inertia can be energy wasted.

This Is Just from reading the fuel display. Next time I fill up I plan on calculating it myself. I just figured it'd be broken in by now at 29k. So I expected better mpgs. I'll update once I calculate it manually.

The big thing that needs to be broken in are the tires; are they new? Also check the tire pressures. The lower, the more energy they take to roll.

Missed that. Tyre pressures can make a HUGE difference to fuel consumption. I bought a car, ran it without checking tyre pressures (weather and other circumstances), checked tyre pressures at next tank full and they were down a few psig. Next top up, with everything else unchanged, returned 10% more mpg!

I never thought of tire pressure, I'll check that today. Thanks

Ignore the dashboard. The only thing you can believe are the numbers you get when you do long division. And yes, tire pressure can make a very big difference in mpg. I run mine 2-3 above the recommended pressure.

Another thing I always do (besides hand-calculate) is to reset the Avg. Fuel Economy calculator at each fill up.

In the Mazda 6 we just got rid of, I did it every time and the car was very close to the hand calculation.

My Honda Jazz resets the Avg. Fuel display every time you reset the trip meter and I always reset that at every fill up. Never touch it between times.