How to Change the Spark Plugs on a Ford Explorer 4.0 Liter SOHCby Russell Wood; Updated November 07, 2017
Items you will need
3/8-inch ratchet and extension
Spark plug socket
Replacement spark plugs
Spark plug gapping tool
As your Ford Explorer starts to accumulate more miles, parts will start to wear out, such as the spark plugs. Although most plugs today can last more than 100,000 miles, that doesn't mean they won't fail sooner. If you're noticing sluggish performance and you have more than 80,000 miles on the vehicle, you may want to consider changing the spark plugs. It's inexpensive and easy to do, and just might fix the problem.
Allow the engine to cool for at least an hour prior to working on it. This will make removing the spark plugs easier. Choose any spark plug wire and remove it from the cylinder head by pulling and twisting it out of the hole.
Remove the spark plug from the engine using the ratchet, extension and spark plug socket. Discard the old plug.
Use the spark plug gapping tool to gap the replacement spark plug to .054 thousandths of an inch. Then, install the replacement plug onto the engine using the ratchet and spark plug socket.
Push the stock spark plug wire back onto the spark plug until it clicks in place.
Repeat steps 1-4 for each spark plug, working your way either clockwise or counterclockwise around the engine. Work on one plug assembly at a time--that way you won't cross or confuse any wires.
- spark image by Zbigniew Nowak from Fotolia.com