+1
My “normal” gas mileage is 22-23 mpg in the winter, and 23-24 mpg in the summer, but during the really cold weather period that we had about 1 month ago, my gas mileage for my usual driving pattern and my usual destinations dropped to 14-18. While I did not like seeing that figure, I didn’t panic because I was confident that the extremely low temps were the cause.
A few days ago–when the temperature was unseasonably high–my mileage jumped to 24 mpg, so I know that instead of mechanical issues, it was merely a plummeting thermometer that was to blame for my really poor mpgs a few weeks earlier.
My mileage was down 3 mpg here in Indiana with the zero degree weather we had. When we got back to near normal winter temperatures the mileage came back up. I am old enough to have owned vehicles with hand chokes. We kept the engines partially choked for longer periods of time in zero degree weather. This made the fuel/air mixture richer, but cut into the mileage. Today’s computer controlled fuel injection does the same thing automatically, so that the fuel mixture is richer with the result drop in mpg. Also, in the old days, in very cold weather we kept the manual transmission in the lower gears for a longer distance. Today’s autos keep the automatic transmissions in the lower gears longer in cold weather. Also, all the moving parts in a car are stiffer in cold weather, and it takes more energy to propel the vehicle.
A lot of good information and suggestions, but this problem started in October before the really cold weather arrived. In Ohio, it was mid-December when the bottom dropped out. I will continue checking mileage (as I always do) to see if it continues to improve.