🔧 Altima - Ignition Coil Replacement

Your Altima’s ignition coils sit on top of the spark plugs and create the high-voltage spark the engine needs to run smoothly. Replacing a weak or failed coil can fix misfires, rough running, and flashing check-engine lights.

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

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⚠️ Safety & Precautions

• ⚠️ Let the engine cool fully before working near the exhaust/engine.
• ⚠️ Keep the key out of the car so the engine can’t be started accidentally.
• ⚠️ Don’t pull on wiring—only press the connector tab and pull the plug.
• ⚠️ If you see oil in the spark plug tube, stop—oil can ruin coils and points to a valve cover/tube seal leak.
• ⚠️ Battery disconnect is optional, but recommended if you’re nervous around electrical connectors.

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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" drive)
• Torque wrench (inch-pound or low-range Nm)
• Flathead screwdriver
• Pick tool (small)
• Shop rags
• Dielectric grease
• OBD2 scan tool (recommended)
• Nitrile gloves
• Safety glasses

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🔩 Required Parts

HowToo sells all the parts you need for this repair:

• Ignition coil - Qty: 1-4
• Ignition coil boot (if separate from coil) - Qty: 1-4
• Engine air intake hose clamp (optional, if damaged) - Qty: 0-1

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📋 Before You Begin

• Park on level ground and set the parking brake.
• Open the hood and let the engine cool for at least 30 minutes.
• If disconnecting the battery: use a 10mm socket to remove the negative battery terminal and isolate it so it can’t spring back.
• Take a quick photo of connectors first.

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🔨 Step-by-Step Instructions

Follow these steps in order:

Step 1: Remove the engine cover (if equipped)

• Use a 10mm socket and 1/4" drive ratchet to remove the engine cover fasteners.
• Lift the cover straight up and set it aside.

Step 2: Locate the ignition coils

• The coils are lined up on top of the valve cover (top of the engine), one per cylinder (4 total).
• Each coil has an electrical connector and a single small hold-down bolt.

Step 3: Unplug the coil electrical connector

• Press the connector locking tab and pull the connector off the coil.
• If it’s stuck, use a flathead screwdriver gently on the tab (don’t pry on the wires).
• A pick tool (small) can help lift the lock tab if it’s tight (a pick is a small pointed hand tool used to lift clips and seals).

Step 4: Remove the coil hold-down bolt

• Use a 10mm socket, 6" extension, and 1/4" drive ratchet to remove the bolt.
• Keep the bolt with that coil so nothing gets mixed up.

Step 5: Remove the ignition coil

• Twist the coil slightly left-right to break the seal, then pull it straight up.
• If it won’t budge, use a little more twisting—avoid using tools to pry on the valve cover.

Step 6: Inspect the coil boot and spark plug tube

• Look down the spark plug tube with a light and check for oil or coolant.
• Wipe any light dirt from the tube opening using shop rags.
• If there’s oil pooled in the tube, don’t install the new coil yet—oil will cause repeat misfires.

Step 7: Install the new coil

• Put a tiny dab of dielectric grease inside the coil boot lip (this helps moisture resistance and makes future removal easier).
• Push the new coil straight down until it fully seats on the spark plug.

Step 8: Reinstall and torque the hold-down bolt

• Start the bolt by hand first to avoid cross-threading.
• Use a 10mm socket to snug it down.
• Use a torque wrench (inch-pound or low-range Nm) and 10mm socket: Torque to 7 Nm (62 in-lbs).

Step 9: Reconnect the electrical connector

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

Step 10: Repeat for any other coils you’re replacing

• Repeat Steps 3-9 for the remaining cylinders as needed.
• One coil at a time prevents mix-ups.

Step 11: Reinstall the engine cover

• Set the cover back in place.
• Use a 10mm socket to reinstall the fasteners snugly (do not over-tighten).

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✅ After Repair

• Reconnect the negative battery terminal (if disconnected) using a 10mm socket.
• Start the engine and let it idle for 1-2 minutes. It should idle smoothly.
• If the check engine light was on, use an OBD2 scan tool to clear codes and confirm the misfire doesn’t return.
• Take a short test drive and recheck for any new warning lights or rough running.

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💰 DIY vs Shop Cost

Shop Cost: $200-$650 (parts + labor)

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

You Save: $160-$330 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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