Does the fuel filter affect gas mileage
there are lots of things that can affect gas mileage. if the spark plugs and wires are worn out, the air filter being dirty, dirty fuel filter, proper inflation of the tires, O2 sensors that are contaminated and performing poorly. the first thing to do would be that the engine is in good working order, as in no check engine light, no misfire, etc. a poorly running engine will put out terrible gas mileage. then you can start with the things i listed.
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