Sittinonthefence is completely right. If the change in temperature has been drastic, this is perfectly normal.
I was averaging 36 mpg in my Accord when the weather was 40-60 degrees.
Now I am averaging 32-33 with the average temperature being 0-20.
ALL VEHICLES GET WORSE FUEL ECONOMY IN COLD WEATHER SINCE A RICHER FUEL MIXTURE IS NEED FOR ENGINE OPERATIION.
COLD AIR IS MORE DENSE THAN WARM AIR OR MORE MOLECULES PER SQUARE INCH. MORE GAS IS METERED TO KEEP STOICHIOMETRIC WINDOW AT OPTIMUM! THIS DROP CAN BE AS MUCH AS 25 PERCENT!
RETIRED ASE MASTER TECH
SITTONTHEFENCE is correct. But I also wanted to add that you could also recheck the tire pressure in the winter, as they will be lower in cold weather as well.
That means that it might be getting colder outside or taking shorter trips.
I have a Ford Freestyle that I got in July. My average mpg (that it displays for me) was usually running around 22mpg. About a month ago, it seemingly "dropped over night" to 19. It now rides right around 18. Ive reset it several times, and even on the highway it says I'm only getting 22mpg, which is 4 lower than what I should be getting.There is no known problems with the car other then dirty transmission fluid. The tires are fine, and I just put in a new air filter. The only thing I figure is that its the transmission fluid or the cold weather. Could that cause it? or what else could it be?
