The fuel economy of a 1994 Ford F-150 with a 300 cubic inch (5.0L) 6-cylinder engine varied depending on several factors including the truck's condition, driving style, and whether it was a 2WD or 4WD model. However, you can expect
somewhere in the range of 14-18 miles per gallon (mpg) combined (city and highway driving). Highway driving might yield slightly better mileage, while city driving would likely be lower.
It's important to remember this is just an estimate. The actual mileage will vary.