Why Replacing The Air Filter In Modern Cars Improves Performance But Not Fuel Economy

One of the go-to upsells at a lot of quick-lube places seems to be changing the air filter. The internet is awash with stories of managers shaking dirty filters at customers and describing how much it needs to be changed, or claiming that driving with a dirty filter will hurt gas mileage. While you should change a dirty filter, that last claim isn't true. If you're driving a modern car with a fuel-injected engine, changing the filter will not make any difference to your gas mileage.
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