* Engine Variations: The 1991 F150 came with a variety of engines (4.9L I6, 5.0L V8, 5.8L V8). Each engine may have a different fuel system setup.
* Filter Locations: Some engines may have a single fuel filter, while others might have two. The location of the filter(s) can also vary.
* Additional Components: Some fuel systems may also have a fuel filter in the fuel pump assembly, especially if it's a fuel-injected system.
How to Find Out:
1. Consult Your Owner's Manual: This is the best place to find information specific to your truck's engine and fuel system.
2. Look Under the Hood: The fuel filter is often located near the fuel lines, under the hood. Check for a cylindrical filter with fuel lines connected to it.
3. Check Online Resources: Search for your specific 1991 F150 engine model (e.g., "1991 Ford F150 5.0L V8 fuel filter") on automotive forums or websites to see what others have found.
Once you know how many fuel filters your truck has, you can easily locate them and determine when they need replacement.
