'05 looking to improve gas mileage
 

New guy here.

I've got a '05 Civic EX automatic and I do a lot of highway driving. When I got the car in '08 with 40k on her I was getting 39 MPG highway pretty regular. Now in winter I'm getting 33'ish MPG at 143k. Plugs are new, gas is 87, engine idles smooth.

I've heard ethanol is a mileage killer but what maintenance can I do to up my gas mileage?

Thanks for any info. Love this little runner. Almost no unplanned maintenance.

Re: '05 looking to improve gas mileage
 

Keep the tires aired up.

Adjust your driving habits.

Don't let the car sit still and run. Any time it's running and you aren't moving down the road, your gas mileage is dropping.

Winter fuel blends, oxygenated fuels, and cold weather, all just kill gas mileage.