Civic getting bad mpg looking for tips.
 

My 2000 civic ex auto is not getting the same mpgs it use to. I use to get 33 to 38 now I'm down to 28 to as bad as 25 at times! Most of my driving is hwy but living in Atlanta speeds are either stopped or 80+mph to not get run over! I have not been using the a.c much. It had a recent tune up and the tires are at 48psi. I don't full throttle it and it never sees over 3500rpm. And tips?

Did the decrease take place after the tune up? If so, something from then might be the cause.

Any other changes to the car or route? 3500rpm is high for fuel economy, is the engine spending more time at higher rpms?

The switch to winter blend happened recently. The change looks too great to be the sole cause, but it will make a minor decrease from something else look worse.

The last time I had a drop like that I had brakes dragging. When I got home I noticed both front rims were warm. I had the calipers replaced and it fixed the problem. I'm guessing the winter blend has something to do with your drop. How long have you had the vehicle and did you notice a drop last winter?