🔧 Focus - Ignition Coil Replacement

Your Focus uses a coil-on-plug ignition system, meaning each spark plug has its own ignition coil sitting right on top of it. Replacing a bad coil can fix misfires, rough idle, and a flashing check-engine light.

Difficulty Level: Beginner | Estimated Time: 0.5-1.0 hours

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⚠️ Safety & Precautions

• ⚠️ Let the engine cool fully before starting (hot parts burn).
• ⚠️ Keep the key away from the car while unplugging coils.
• ⚠️ If you disconnect the battery, you may lose radio presets.
• ⚠️ Don’t pull on wiring—always pull on the connector body.

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🔧 Required Tools

You'll need the following tools for this repair:

• 10mm socket
• 1/4" ratchet
• 3" extension for 1/4" ratchet
• Small flathead screwdriver
• Torque wrench (in-lb range)
• Needle-nose pliers
• Shop towel
• Nitrile gloves
• Safety glasses

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🔩 Required Parts

HowToo sells all the parts you need for this repair:

• Ignition coil - Qty: 1 (or Qty: 4 if replacing all)
• Dielectric grease - Qty: 1

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📋 Before You Begin

• Park on level ground and turn the ignition OFF.
• Open the hood and make sure the engine is cool to the touch.
• If you want maximum safety: disconnect the negative battery terminal using a 10mm socket.

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🔨 Step-by-Step Instructions

Follow these steps in order:

Step 1: Remove the engine cover (if equipped)

• Grip the cover with your hands and pull upward evenly to pop it off the rubber mounts.
• If your cover uses fasteners on your Focus, remove them with a 10mm socket and 1/4" ratchet.
• Pull straight up to avoid cracking it.

Step 2: Locate the ignition coils

• You’ll see 4 coils in a row on top of the valve cover, each with an electrical connector.
• Wipe any loose dirt away with a shop towel so nothing falls into the spark plug holes.

Step 3: Unplug the coil electrical connector

• Use a small flathead screwdriver to gently lift the connector lock tab (if present), then pull the connector straight off.
• If it’s stubborn, use needle-nose pliers carefully on the connector body (not the wires).

Step 4: Remove the coil hold-down bolt

• Remove the coil bolt using a 10mm socket, 1/4" ratchet, and 3" extension.
• Set the bolt aside where it won’t get lost.

Step 5: Remove the ignition coil

• Twist the coil slightly left-right to break the seal, then pull it straight up by hand.
• If it feels stuck, keep twisting gently—don’t pry hard against the valve cover.

Step 6: Prep and install the new coil

• Put a small dab of dielectric grease inside the new coil boot (the rubber end). This helps sealing and makes future removal easier.
• Push the coil straight down until you feel it fully seat onto the spark plug.
• Reinstall the hold-down bolt using the 10mm socket and 1/4" ratchet.
• Tighten with a torque wrench (in-lb range): Torque to 7 Nm (62 in-lb).

Step 7: Reconnect the electrical connector

• Push the connector on until it clicks/locks.
• Give it a gentle tug to confirm it’s latched.

Step 8: Reinstall the engine cover

• Press the cover straight down onto the mounts.
• If your Focus uses fasteners, reinstall them with a 10mm socket.

Step 9: Reconnect the battery (if disconnected)

• Reconnect the negative battery terminal using a 10mm socket.

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✅ After Repair

• Start the engine and let it idle for 1-2 minutes. It should run smooth.
• If the check-engine light was flashing before, it should stop flashing immediately once the misfire is gone.
• If the check-engine light stays on, the code may need to be cleared after the repair.
• Road test for 10 minutes and recheck that all connectors are fully seated.

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💰 DIY vs Shop Cost

Shop Cost: $180-$500 (parts + labor, depending on 1 coil vs all 4)

DIY Cost: $40-$320 (parts only)

You Save: $140-$180+ by doing it yourself!

Shop labor rates vary but typically run $100-$150/hour. This repair takes a shop approximately 0.5-1.0 hours.

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🎯 Ready to get started?

HowToo makes it easy: same-day/2-day shipping on every part, plus all the tools and specialty tools you need! Check out the parts and tools sections below to add everything to your cart.