You can experiment with different brands of fuel. In cold winter months, cars tend to get poorer milage. The engine runs richer until it warms up. Headlights can be on for longer periods of time, the alternator has to make up the load, which puts additional drag on the engine. On many cars, when the defroster is on, the air conditioner runs to remove humidity from the air.
Summer time can also drop.
If the air conditioner is used a lot, it puts additional load on the engine. At highway speeds, it is offset somewhat by reduced air drag on the vehicle by having windows closed. Tried accelerating easier since last fill. Gallons used since last fill up. Return to AutoTips home page.