🔧 Focus - Ignition Coil Replacement

Your Focus uses one ignition coil per cylinder (coil-on-plug). Replacing a bad coil restores smooth running and can fix misfires, rough idle, and a flashing check engine light.

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

Assumption: 2.0L uses 8mm coil hold-down bolts.

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⚠️ Safety & Precautions

• ⚠️ Work on a cool engine to avoid burns.
• ⚠️ Keep tools away from the battery positive terminal to prevent sparks.
• ⚠️ Do not pull on wiring; pull on connectors only.
• ⚠️ Battery disconnect is not required, but disconnecting the negative terminal is recommended if you’re nervous around electrical connectors.

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🔧 Required Tools

You'll need the following tools for this repair:

• Safety glasses
• Nitrile gloves
• 1/4" drive ratchet
• 1/4" drive extension set
• 8mm socket
• 10mm socket
• Small flat trim tool
• Torque wrench (in-lb or Nm capable)

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🔩 Required Parts

HowToo sells all the parts you need for this repair:

• Ignition coil - Qty: 4
• Dielectric grease - Qty: 1
• Engine air intake/engine cover fasteners (optional) - Qty: 1

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📋 Before You Begin

• Park on level ground and set the parking brake.
• Let the engine cool fully.
• If disconnecting the battery: use a 10mm socket to remove the negative terminal and keep it from touching the post.
• Lay the new coils out in order so you don’t mix anything up.

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🔨 Step-by-Step Instructions

Follow these steps in order:

Step 1: Remove the engine cover (if equipped)

• Remove any retaining nuts/bolts using a 10mm socket (some covers use 8mm socket).
• Lift the cover straight up and set it aside.

Step 2: Locate the ignition coils

• The coils sit on top of the engine, lined up in a row over the spark plugs.
• One coil = one cylinder.

Step 3: Unplug the coil electrical connector

• Press the connector lock tab and pull the connector straight off by hand.
• If it’s stubborn, gently assist with a small flat trim tool (a plastic/flat prying tool used to release clips without breaking them).

Step 4: Remove the coil hold-down bolt

• Use an 8mm socket with a 1/4" drive ratchet and 1/4" drive extension to remove the bolt.
• Set the bolt somewhere safe so it doesn’t fall into the engine bay.

Step 5: Remove the ignition coil

• Grab the coil body, twist it slightly left-right to break the seal, then pull straight up.
• If the coil boot sticks, keep twisting gently—don’t pry hard on the valve cover.

Step 6: Prep and install the new coil

• Apply a tiny smear of dielectric grease inside the rubber boot (this is a non-conductive grease that helps prevent moisture and makes future removal easier).
• Push the new coil straight down until it fully seats on the spark plug.
• Reinstall the hold-down bolt using the 8mm socket.
• Tighten the coil bolt with a torque wrench (a tool that tightens to an exact setting): Torque to 7 Nm (62 in-lb).

Step 7: Reconnect the coil connector

• Push the connector on until it clicks/locks.
• Gently tug back to confirm it’s secure.

Step 8: Repeat for the remaining coils

• Replace coils one at a time so you don’t mix up connectors or bolts.

Step 9: Reinstall the engine cover

• Set the cover back in place.
• Reinstall fasteners using a 10mm socket (or 8mm socket if that’s what yours uses).
• Snug them down evenly (no need to over-tighten).

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✅ After Repair

• Reconnect the battery negative terminal (if disconnected) using a 10mm socket.
• Start the engine and let it idle for 1-2 minutes. It should run smooth with no shaking.
• If the check engine light was on, it may take a few drive cycles to clear, or you can clear codes with a scan tool.
• Test drive for 10-15 minutes and verify there’s no hesitation under acceleration.

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💰 DIY vs Shop Cost

Shop Cost: $250-$550 (parts + labor)

DIY Cost: $120-$320 (parts only)

You Save: $130-$230 by doing it yourself!

Shop labor rates vary but typically run $100-$150/hour. This repair takes a shop approximately 0.7-1.0 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.