🔧 Spark Plugs - Replacement

Your F-150 uses coil-on-plug ignition, so each spark plug sits under its own ignition coil. The job is straightforward, but the plugs must come out on a fully cold engine to reduce the chance of thread damage in the aluminum heads.

Difficulty Level: Intermediate | Estimated Time: 2-4 hours

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⚠️ Safety & Precautions

• Let the engine cool completely before starting. Hot aluminum threads can strip more easily.
• Disconnect the negative battery cable before removing ignition coils.
• Keep dirt out of the spark plug wells. Debris can fall into the cylinder if not cleaned first.
• Do not use power tools to install spark plugs.
• Use the correct torque. Overtightening can damage the cylinder head.
• Tip: Work on one cylinder at a time.

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🔧 Required Tools

You'll need the following tools for this repair:

• 1/4-inch drive ratchet
• 3/8-inch drive ratchet
• 6-inch extension
• 8mm socket
• 10mm socket
• 5/8-inch spark plug socket
• Torque wrench
• Flat trim tool
• Compressed air or air blower
• Dielectric grease
• Gloves
• Safety glasses
• Shop towels

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🔩 Required Parts

HowToo sells all the parts you need for this repair:

• Spark plugs - Qty: 8
• Ignition coil boots - Qty: 8, replace if torn or oil-soaked

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📋 Before You Begin

• Park on level ground and set the parking brake.
• Let the engine cool fully.
• Disconnect the negative battery cable before starting.
• Open the hood and clean around the coil and plug areas before removal.

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🔨 Step-by-Step Instructions

Follow these steps in order:

Step 1: Remove engine cover and intake ducting

• Use a flat trim tool to lift off the engine cover, if equipped.
• Use an 8mm socket to loosen the air intake clamp and remove any ducting blocking access.
• Set the parts aside in order so they go back the same way.

Step 2: Disconnect battery power

• Use a 10mm socket to disconnect the negative battery cable.
• Move the cable aside so it cannot spring back to the terminal.

Step 3: Remove the ignition coil from one cylinder

• Use an 8mm socket to remove the ignition coil hold-down bolt.
• Pull the coil straight up and out by hand.
• Tip: Twist slightly if the boot sticks.

Step 4: Clean the spark plug well

• Use compressed air or an air blower to clear dirt from the spark plug well.
• Make sure no debris can fall into the cylinder when the plug comes out.

Step 5: Remove the old spark plug

• Use a 5/8-inch spark plug socket, 6-inch extension, and 1/4-inch drive ratchet to loosen and remove the spark plug.
• Turn slowly at first. If it feels tight, stop and work it back and forth gently.
• If a plug feels stuck, do not force it.

Step 6: Install the new spark plug

• Check that the new spark plug is the correct type and is pre-gapped.
• Thread it in by hand first using the 5/8-inch spark plug socket and extension.
• Once seated, use a torque wrench to tighten to 13 Nm (115 in-lbs).
• Tip: Hand-starting prevents cross-threading.

Step 7: Reinstall the ignition coil

• Add a small amount of dielectric grease inside the coil boot if desired.
• Push the coil straight down onto the spark plug.
• Use an 8mm socket to install the coil hold-down bolt and tighten snugly. Do not overtighten.

Step 8: Repeat for all cylinders

• Repeat Steps 3 through 7 for the remaining 7 spark plugs.
• Work one cylinder at a time so parts do not get mixed up.

Step 9: Reinstall intake parts and reconnect battery

• Reinstall any intake ducting and tighten the clamp with an 8mm socket.
• Reinstall the engine cover, if equipped.
• Reconnect the negative battery cable using a 10mm socket.

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✅ After Repair

• Start the engine and listen for a smooth idle.
• Check the dash for a misfire or check engine light.
• If the engine runs rough, recheck coil seating and plug torque.
• Take a short test drive and make sure acceleration feels normal.

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💰 DIY vs Shop Cost

Shop Cost: $250-$500 (parts + labor)

DIY Cost: $60-$160 (parts only)

You Save: $190-$340 by doing it yourself!

Shop labor rates vary but typically run $100-$150/hour. This repair takes a shop approximately 2-4 hours.

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🎯 Ready to get started?

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