🔧 Altima - Ignition Coil Replacement

Your Altima uses 4 ignition coils (one per cylinder) to fire the spark plugs. Replacing a bad coil can fix misfires, rough idle, and a flashing check engine light.

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

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⚠️ Safety & Precautions

• ⚠️ Let the engine cool completely before starting (coils sit on the hot valve cover).
• ⚠️ Disconnect the negative battery cable to prevent accidental shorts.
• ⚠️ Do not pull on the wiring harness—only unplug connectors by the lock tab.
• ⚠️ If the check engine light is flashing, avoid driving until repaired (can damage the catalytic converter).

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🔧 Required Tools

You'll need the following tools for this repair:

• 10mm socket
• 3/8" ratchet
• 3" socket extension
• Inch-pound torque wrench (50-200 in-lb)
• Flat-blade screwdriver
• Trim clip tool
• OBD-II scan tool
• 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 open the hood.
• 🔋 Use a 10mm socket to disconnect the negative battery cable and set it aside so it can’t spring back.
• 🧠 If you have an OBD-II scan tool (a plug-in code reader), pull codes first so you know which cylinder was misfiring (example: P0302 = cylinder 2).

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🔨 Step-by-Step Instructions

Follow these steps in order:

Step 1: Remove the top cover/air ducting (if equipped)

• If your Altima has a plastic engine cover, remove its fasteners using a 10mm socket and 3/8" ratchet, then lift it off.
• If the intake duct blocks access, loosen its clamps using a flat-blade screwdriver and move the duct aside.
• Use a trim clip tool if you encounter plastic push-clips.

Step 2: Locate the ignition coils

• The coils are on top of the engine, each sitting directly over a spark plug.
• Each coil has an electrical connector and a single small hold-down bolt.

Step 3: Unplug the coil electrical connector

• Press the connector lock tab and pull the connector straight off the coil.
• If it’s stuck, wiggle gently—don’t yank.

Step 4: Remove the coil hold-down bolt

• Use a 10mm socket, 3/8" ratchet, and 3" socket extension to remove the bolt.
• Set the bolt somewhere safe (dropping it can be a hassle).

Step 5: Remove the ignition coil

• Twist the coil slightly left and right to break the seal, then pull it straight up.
• If it feels glued in place, keep twisting while pulling upward—do not pry hard on the valve cover.

Step 6: Install the new ignition coil

• Put a tiny dab of dielectric grease inside the coil boot (this helps prevent moisture; it’s a non-conductive grease).
• Push the coil straight down until it fully seats on the spark plug.

Step 7: Reinstall and torque the coil bolt

• Start the bolt by hand first to avoid cross-threading.
• Use an inch-pound torque wrench (50-200 in-lb) with a 10mm socket to tighten the bolt.
• Torque to 64 in-lb (7.2 Nm)

Step 8: Reconnect the electrical connector

• Push the connector on until it clicks.
• Give it a light tug to confirm it’s locked.

Step 9: Repeat for other coils (if needed)

• If you’re replacing all coils, repeat Steps 3–8 for the remaining cylinders.
• If you’re replacing only one coil, double-check you did the correct cylinder before reassembling.

Step 10: Reinstall covers/ducting and reconnect the battery

• Reinstall any intake ducting you moved using a flat-blade screwdriver.
• Reinstall the engine cover (if equipped) using a 10mm socket and 3/8" ratchet.
• Reconnect the negative battery cable using a 10mm socket.

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✅ After Repair

• 🔎 Start the engine and let it idle for 1–2 minutes. The idle should be smooth.
• 🧪 Take a short test drive. Verify there’s no hesitation under acceleration.
• 🧰 If the check engine light was on, use an OBD-II scan tool to clear codes, then re-check for returning misfire codes.
• 👃 If you smell raw fuel or the engine runs worse, shut it off and re-check the coil connector is fully clicked in.

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💰 DIY vs Shop Cost

Shop Cost: $200-$600 (parts + labor, depends how many coils)

DIY Cost: $40-$320 (parts only, depends how many coils)

You Save: $160-$280 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?

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