Ford V10 gradual reduction in fuel economy
I have a 26' Class C on a 2000 Ford E450 chassis with V10 engine now with 115,000 mile on it. I used to average 8.5 mpg pulling a 3400 lb toad but over time the economy has deteriated to the 7.5 to 8....
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Have the spark plugs been replaced? If not, they're probably at (or beyond) the end of their useful life.
Oxygen sensors do age, and are relatively inexpensive and easy to replace. If they're only somewhat out of calibration they may not cause check engine lights but still affect mileage some (and possibly catalytic converter life), or so I've been led to believe. Replacing them might be a reasonable thing to try. For that matter, if the catalytic converters are getting plugged from soot or whatever, that can affect engine performance as well.
Oxygen sensors do age, and are relatively inexpensive and easy to replace. If they're only somewhat out of calibration they may not cause check engine lights but still affect mileage some (and possibly catalytic converter life), or so I've been led to believe. Replacing them might be a reasonable thing to try. For that matter, if the catalytic converters are getting plugged from soot or whatever, that can affect engine performance as well.
