🔧 Lancer - Ignition Coil Replacement

Your Lancer’s ignition coils sit on top of the spark plugs and create the high voltage needed to fire each cylinder. Replacing a weak coil can fix misfires, rough idle, and loss of power. This is a straightforward under-hood job with basic hand tools.

Difficulty Level: Beginner | Estimated Time: 0.5-1.5 hours

Assumption: 2.4L 4B12 engine coil hold-down torque ~9 Nm.

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⚠️ Safety & Precautions

• ⚠️ Work on a cool engine to avoid burns.
• ⚠️ Disconnect the negative battery terminal to prevent accidental short circuits.
• ⚠️ Pull on the coil body, not the wiring, to avoid harness damage.
• ⚠️ Keep dirt out of the spark plug tubes; debris can cause misfires.

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🔧 Required Tools

You'll need the following tools for this repair:

• 10mm socket
• 1/4" drive ratchet
• 6" extension (1/4")
• Torque wrench (2-25 Nm range)
• Flat trim tool
• Needle-nose pliers
• Flashlight
• Nitrile gloves
• Safety glasses

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🔩 Required Parts

HowToo sells all the parts you need for this repair:

• Ignition coil - Qty: 1
• Ignition coil set (replace all four) - Qty: 1
• Dielectric grease - Qty: 1
• Intake/engine cover grommets or clips - Qty: 1

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📋 Before You Begin

• Park on level ground, shift to Park, and set the parking brake.
• Let the engine cool fully.
• Open the hood and disconnect the battery negative terminal using a 10mm socket.
• Lay out coils in order (cylinders 1-4) so nothing gets mixed up.

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🔨 Step-by-Step Instructions

Follow these steps in order:

Step 1: Remove the engine cover (if equipped)

• Use a flat trim tool to gently pop up any cover fasteners (if present).
• Lift the cover straight up and off. Use a flashlight to confirm the ignition coils are visible on top of the valve cover.

Step 2: Unplug the coil electrical connector

• At the first coil, press the connector lock tab and pull the connector straight back.
• If the tab is stubborn, use needle-nose pliers carefully (do not crush the connector).
• Wiggle the connector, don’t yank.

Step 3: Remove the coil hold-down bolt

• Use a 10mm socket, 6" extension (1/4"), and 1/4" drive ratchet to remove the single bolt holding the coil down.
• Set the bolt aside where it can’t fall into the engine bay.

Step 4: Remove the ignition coil

• Grip the coil body and twist slightly left-right to break the boot seal.
• Pull the coil straight up out of the spark plug tube.
• Use a flashlight to look down the tube—remove any loose dirt with a clean rag (do not drop anything inside).

Step 5: Prep and install the new coil

• Put a small dab of dielectric grease inside the rubber boot of the new coil.
• Push the new coil straight down until you feel it seat on the spark plug.
• Reinstall the hold-down bolt by hand first to avoid cross-threading.
• Tighten using a torque wrench (2-25 Nm range): Torque to 9 Nm (80 in-lbs).

Step 6: Reconnect the coil connector

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

Step 7: Repeat for remaining coils

• Repeat Steps 2-6 for the other coils.
• If you’re chasing a misfire on one cylinder, it’s still smart to inspect the others for oil in the plug tubes or cracked boots.

Step 8: Reinstall the engine cover and reconnect the battery

• Reinstall the engine cover and press it into place.
• 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 with no flashing check engine light.
• If the check engine light was on, use a scan tool to clear codes and confirm no misfire codes return.
• Take a 10-minute test drive with light and moderate throttle.
• Recheck that all coil connectors are fully clicked in if you feel any stumble.

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💰 DIY vs Shop Cost

Shop Cost: $250-$650 (parts + labor)

DIY Cost: $60-$400 (parts only)

You Save: $190-$250+ by doing it yourself!

Shop labor rates vary but typically run $100-$150/hour. This repair takes a shop approximately 0.7-1.2 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.