Poor Gas Consumption - 2006 Honda Civic EX

I was getting 29 mpg (no a/c, closed windows, only 2 adults with total weight of 280 lb, trunk empty, proper tire pressure, no aggressive driving/acceleration, no hills) with my 2006 Honda Civic EX first few years.

These days I am getting 20-24 mpg, driving very gently. Nothing has changed, except the car is older.

Does this explain in this poor gas consumption? Is there anything wrong with the car? Can I do anything about this?

Volkan Akkurt

How many miles are on the car? Is the maintenance up to date?