theocean,
Well, I don't have a lot to add, and agree with everyone here, but high 20's and low 30's does seem strange, especially with the weather a little warmer now. I got 43 mpg my first tank, driving fairly slowly but not using any hypermile techniques.

Are you CERTAIN that the A/C is not operating? Try turning the environment controls to OFF, then turn the fan speed (right knob) a click or two. Push the AC button and the display should say AC OFF. Drive like that for awhile and see if it helps, adjusting only the temperature knob and fan knob for comfort. This darn thing just doesn't do a good job of telling you when AC is on.

Also, drive slowly and avoid rapid starts, and see if that helps. On downhill glides with light pressure on the gas you should be able to get the instantaneous MPG to go to 100. At the very least it should go to 100 with your foot off the gas while coasting downhill. Make sure this all looks normal.

And as has been said here, very short trips (5 miles or less) on a cold engine will kill your mpg. Try resetting your Trip B every time you take a trip, and watch what your trip mileage ends up being. You will see how very bad it is during the first few miles.

Is it autostopping like you would expect? Once the engine is warmed up, or even sooner on a warm day when it's been sitting in the sun (70+ degrees), you should get autostop. Also, bumper to bumper traffic can kill mpg.

As also suggested, give it some time and see if it comes around. If it doesn't, write as much about how you drive and how it behaves as possible here - there are lots of people who will help (as you've already seen).

Congratulations on your new purchase!!