[jjones22]

Pretty much I'm driving a hummer. I get 12mpg or less. Don't small gas anywhere. Check engine light comes on periodically. Don't know what the problem is.

[TxGreaseMonkey]

If you perform all of the steps in the link below, your Civic should get 35+ MPG:

https://www.askmehelpdesk.com/cars-t...tml#post293582

. Check for DTCs--your oxygen sensor and/or Engine Coolant Temperature (ECY) Sensors may be bad and directly affect gas mileage. Jump the Service Check Connector (SCC) with a paper clip, turn ignition to ON (Position II), and count Check Engine Light flashes. The SCC is located in a rubber mount under the glove box, approximately 1" from the kick panel. Use a small screwdriver to carefully pry it out.
. Check engine timing:

https://www.askmehelpdesk.com/cars-t...tml#post219963

. Replace spark plugs (NGK only).
. Replace air and fuel filter.

My 1993 Civic gets 42 MPG around town and up to 56 MPG on the road.