I read what follows on this site about changing the air filter. I fail to grasp why the fuel and fuel filter are mentioned.

How to Change the Air Filter of Your Ford Truck:

Step 1

Before you start to change the air filter of your truck, keep a new air filter, a socket wrench, a jack, a basin and a screw driver at hand.
Step 2

Ensure that you check your truck owner’s manual and buy an air filter that’s suitable for your truck.
Step 3

Park the truck on a flat surface and use a jack to raise the driver’s side of the truck.
Step 4

Remove the fuel pressure by first removing the gas cap on the gas tank and then removing the fuse to the fuel pump. The fuel pump is generally located under the hood on the driver’s side of the vehicle. Once there is no fuel pressure, you can replace the gas cap.
Step 5

Lift the hood of your truck and identify the air-filter housing unit on the driver’s side of the car. Try to find the location of the fuel filter. It’s located near the fuel tank that’s mounted on the frame rail under the driver’s seat. It’s connected to the fuel tank by a fuel pipe and can be easily identified as a silver, cylindrical container.
Step 6

Place a basin under the fuel filter so that any fuel that leaks accumulates in the basin and doesn’t go waste.
Step 7

Remove the lid of the air-filter housing unit with the help of a screwdriver.
Step 8

Disconnect the old filter by unbolting the clamp that holds in place, with the use of a socket wrench.
Step 9

Remove the old filter and also clean the air filter unit with a damp cloth to remove any dirt.
Step 10

Place the new filter inside the unit and clamp it in place and connect the fuel line to the filter. You should hear a click when the fuel line connects with the filter.
Step 11

Replace the lid of the unit and lower the truck to ground level.
Step 12

Then close the hood of the truck and start the truck.
Step 13

Check to see if there is any leakage while the engine is running.
Step 14

Once you are sure that the air filter is in place and there is no leakage, you may turn off the engine.