Hi

 

somethings definitely not right there. I also have an 06, but with a manual transmission and I am getting 450-500 miles to a tank mixed city and highway and close to 600 miles on a long road trip I took last month. Fill up and see how much you are getting to a tank as opposed to looking at the navigation readout.

 

The navigation screen may be incorrectly calculating the avg mpg.

Fill up with gas to full, reset the trip meter. When you fill up again, divide the total trip miles by the number of gallons at this next fill up to get your avg. mpg.

 

city miles + cold engine(running rich) = bad gas mileage. And dont stomp on the car when its warming up, that will lead to massive engine wear.

 

I got 30+ mpg in the city this summer in my MINI, and now i'm getting in the 20's when it hasn't warmed up fully. Overall fuel economy has dropped for me.

It just happens in the winter with cold air and cold starts.

Recheck manually like someone said above and it if persists then get it checked out.

I only averaged about 20 city overall in my old 4 cyl Accord.

 

If it is really cold where you are that will contribute to your poor gas mileage. Have you done a tune up on the car recently?