That sounds like a
fuel filter. While some fuel filters are larger and more obvious, many, especially on older vehicles like a 1985 Ford F-150, are smaller and cylindrical, often appearing silver or metallic. They are in the fuel line and act as a valve in the sense that they restrict the flow of fuel if there is excessive debris.
It's unlikely to be another type of valve in that location unless it's a very unusual aftermarket addition. A fuel filter is the most probable answer.
