2003 Toyota Highlander 6 cyl Four Wheel Drive Automatic 85000 miles
Recently I have noticed that fuel economy on my highlander has suddenly dropped. I used to get around 18 to 20 mpg and now it is more like 16mpg, with mixed driving. I have replaced the new air filter but have not seen any improvement. Any clues or suggestions.
Your profile doesn t list your location so I can't say if this issue applies to your area.
Many parts of the U.S. Switch to an extra oxygenated fuel during the late fall through the winter. Heavier oxygenated gas is cleaner burning measured by the amount carbon monoxide at the tail pipe. Because the time to warm up your engine is longer due to the cold weather, the "winter gas" adds the necessary oxygen to bind with the CO molecule and creates CO2, carbon dioxide/the same stuff we breathe out. Unfortunately it does not burn as thoroughly as gasoline once the engine is warmed. There is a really long explanation as to what happens so I am abridging it.
In short, fuel economy will fall during these times of year if your state mandates the use of oxygenated gasoline. Next time you fill up, read the stickers on the pump, there is often a sign that mentions the new gas mixture.
Please note, areas on the map are mandated, many states voluntarily participate. If this fix does not apply to you, PLEASE post back and we can explore other options.