Question about 1990 Ford F150

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Burning fuel too rich spark plugs are very black

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Hi, the colour of the plugs may not mean too rich, may be oily deposits from oil passing the piston rings or passing the VALVE GUIDES, or brakes binding, tyre pressure incorrect or truck always loaded with stuff. you may be right plug colour (light tan with white deposits). if all the plugs are the same colour then i suggest check and clean M AF sensor or HO2 sensor. gerry

Posted on Sep 08, 2010


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