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Q: The car has a decrease in gas mileage

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I have a well-maintained car that has been running great with no major problems. Except for the poor gas mileage issue, for which I went to the dealership but was told that nothing is wrong. This problem started occuring several months ago. Up to now, the miles per gallon decreased 23% and I would like to know why. I haven't changed anything in my driving habits so this is very unusal. What could cause this? What can I do to improve gas mileage?

A: Hello. For a sudden drop like this to occur...

Hello. For a sudden drop like this to occur, it usually means that a sensor it not reading correctly. I usually install a scan tool first to check things like the oxygen sensors and the air flow meter as they are the most common causes of a drop in MPG. If nothing is found, then I clean out the air flow meter and reset the computer and that usually takes care of it. If you need to have this checked, consider YourMechanic, as a certified mechanic can come to your home or office to inspect your fuel system and let you if any adjustments or repairs should be made. It is possible that the decrease in MPG could merely be a result of a change in recent driving habits.

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