🔧 Spark Plugs - Replacement

Your F-150 uses six spark plugs, one for each cylinder. This job is straightforward, but the plugs sit deep in the cylinder heads, so clean work and the right sockets matter. Replacing them on time helps prevent misfires, rough idle, and poor fuel economy.

Difficulty Level: Intermediate | Estimated Time: 2-3 hours

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⚠️ Safety & Precautions

• Work on a cold engine only. Hot aluminum threads can be damaged easily.
• Disconnect the negative battery cable before starting to reduce the chance of accidental cranking.
• Use care around ignition coils. Do not pull on the wiring.
• Keep dirt out of the plug wells. Debris can fall into the cylinders when the plug is removed.
• If any plug feels stuck, stop and work it out slowly to avoid breaking it.

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🔧 Required Tools

You'll need the following tools for this repair:

• 10mm socket
• 3/8-inch drive ratchet
• 3-inch extension
• 6-inch extension
• Spark plug socket 5/8-inch
• Torque wrench
• Trim tool
• Compressed air
• Dielectric grease
• Gloves
• Safety glasses

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🔩 Required Parts

HowToo sells all the parts you need for this repair:

• Spark plugs - Qty: 6

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📋 Before You Begin

• Park on level ground and set the parking brake.
• Let the engine cool completely.
• Open the hood and disconnect the negative battery cable.
• Label coil connectors if you want extra confidence.

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🔨 Step-by-Step Instructions

Follow these steps in order:

Step 1: Remove the engine cover and intake ducting

• Use a trim tool to remove the engine cover, if equipped.
• Use a 10mm socket to loosen the air intake duct clamps and remove the ducting if it blocks access to the rear plugs.
• Set the parts aside in order.

Step 2: Remove the ignition coil connectors

• Work on one cylinder at a time so nothing gets mixed up.
• Unplug each coil connector by pressing the lock tab and pulling straight back.
• Do not tug on the wires.

Step 3: Remove the ignition coils

• Use a 10mm socket and ratchet to remove the coil hold-down bolts.
• Twist each coil gently, then pull it straight up out of the plug well.
• Inspect the boots for oil, cracks, or burns.

Step 4: Clean the spark plug wells

• Use compressed air to blow dirt out of each plug well before removing the plug.
• This keeps debris from falling into the cylinder.

Step 5: Remove the old spark plugs

• Use a 5/8-inch spark plug socket, extension, and ratchet to loosen each plug.
• Turn slowly and keep the socket aligned so the plug does not cross-thread.
• Remove one plug at a time and compare it to the new one.

Step 6: Install the new spark plugs

• Check the gap on each new plug before installing. Do not force the gap change unless needed.
• Thread each plug in by hand first using the extension only.
• Once seated, use a torque wrench and 5/8-inch spark plug socket to torque to 13 Nm (115 in-lbs).
• Hand-start every plug to avoid cross-threading.

Step 7: Reinstall the ignition coils

• Apply a small amount of dielectric grease inside each coil boot.
• Push each coil straight down onto its plug until fully seated.
• Install the coil bolts with a 10mm socket and torque to 8 Nm (71 in-lbs).
• Reconnect each coil connector until it clicks.

Step 8: Reinstall the intake parts and cover

• Reinstall any intake ducting removed earlier.
• Tighten the clamps with a 10mm socket.
• Reinstall the engine cover.
• Reconnect the negative battery cable.

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✅ After Repair

• Start the engine and let it idle for a minute.
• Listen for smooth idle and check for misfire or warning lights.
• If the engine runs rough, recheck coil connectors and plug installation.
• Take a short test drive and confirm normal power delivery.

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💰 DIY vs Shop Cost

Shop Cost: $250-$450 (parts + labor)

DIY Cost: $45-$120 (parts only)

You Save: $205-$330 by doing it yourself!

Shop labor rates vary but typically run $100-$150/hour. This repair takes a shop approximately 2-3 hours.

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🎯 Ready to get started?

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