🔧 Spark Plugs - Replacement

Your Accord uses four coil-on-plug spark plugs under the engine cover. Replacing them can fix rough idle, poor fuel economy, hesitation, and hard starting when the plugs are worn out.

Difficulty Level: Intermediate | Estimated Time: 1.5-2.5 hours

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⚠️ Safety & Precautions

• Let the engine cool completely before opening the ignition area. Hot aluminum threads can be damaged easily.
• Disconnect the negative battery cable with a 10mm wrench before unplugging ignition coils.
• Keep dirt and sand out of the spark plug tubes. Debris can fall into the cylinder.
• Do not over-tighten the new plugs. The cylinder head is aluminum and can strip.
• Use care with the ignition coils. Pull them straight up and do not twist hard.

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🔧 Required Tools

You'll need the following tools for this repair:

• 10mm wrench
• 10mm socket
• 3/8-inch ratchet
• 6-inch extension
• 5/8-inch spark plug socket
• Torque wrench
• Trim clip tool
• Compressed air
• Feeler gauge
• Dielectric grease
• Safety glasses
• Mechanic gloves

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🔩 Required Parts

HowToo sells all the parts you need for this repair:

• Spark plug set - Qty: 4

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📋 Before You Begin

• Park on level ground and set the parking brake.
• Make sure the engine is fully cool.
• Open the hood and remove the engine cover.
• Disconnect the negative battery cable using a 10mm wrench.

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🔨 Step-by-Step Instructions

Follow these steps in order:

Step 1: Remove the engine cover

• Lift the engine cover straight up to release it from its rubber mounts.
• Set it aside where it will not crack or get dirty.

Step 2: Remove the ignition coils

• Use a trim clip tool to move any clips or hoses that block access.
• Press the lock tab and unplug each ignition coil connector.
• Use a 10mm socket and 3/8-inch ratchet to remove each coil hold-down bolt.
• Pull each coil straight up out of the plug tube.
• Keep each coil in order.

Step 3: Clean the spark plug wells

• Use compressed air to blow dirt out of the plug wells before removing the plugs.
• This helps keep debris out of the engine.

Step 4: Remove the old spark plugs

• Use a 5/8-inch spark plug socket, 6-inch extension, and 3/8-inch ratchet to loosen each plug.
• Turn counterclockwise until the plug is free.
• Finish removing each plug by hand.
• Inspect the old plugs for oil, heavy wear, or white deposits.

Step 5: Install the new spark plugs

• Check the plug gap with a feeler gauge. Use the gap listed on the plug package if adjustment is needed.
• Thread each plug in by hand first using the spark plug socket and extension.
• Once seated, tighten each plug with a torque wrench to 25 Nm (18 ft-lbs).
• Start every plug by hand first.

Step 6: Reinstall the ignition coils

• Add a small amount of dielectric grease inside each coil boot.
• Push each coil straight down onto its spark plug.
• Install the coil bolts with a 10mm socket and tighten to 12 Nm (9 ft-lbs).
• Reconnect each coil connector until it clicks.

Step 7: Reinstall the engine cover

• Align the cover with its mounting points.
• Press down firmly until it seats fully.

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✅ After Repair

• Reconnect the negative battery cable with a 10mm wrench.
• Start the engine and let it idle.
• Check for a smooth idle and no warning lights.
• If the check engine light comes on, scan for misfire codes.
• Take a short test drive and confirm normal acceleration.

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💰 DIY vs Shop Cost

Shop Cost: $180-$320 (parts + labor)

DIY Cost: $40-$90 (parts only)

You Save: $140-$230 by doing it yourself!

Shop labor rates vary but typically run $100-$150/hour. This repair takes a shop approximately 1.0-1.5 hours.

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🎯 Ready to get started?

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