🔧 Altima - Ignition Coil Replacement

Replacing the ignition coils on your Altima is a beginner-friendly repair. The coils sit on top of the engine and send spark to the spark plugs; a bad coil can cause rough idle, misfires, poor fuel economy, or a flashing check engine light.

Difficulty Level: Beginner | Estimated Time: 30-60 minutes

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⚠️ Safety & Precautions

• ⚠️ Let the engine cool completely before starting so you do not burn your hands.
• 🔋 Disconnect the negative battery cable before unplugging ignition coils.
• ⚡ Ignition coils make high voltage while the engine runs. Never touch or unplug them with the engine running.
• 🧼 Keep dirt out of the spark plug tubes. Dirt can fall into the engine when the coil is removed.
• 🔧 Do not overtighten the small coil bolts. They thread into aluminum and can strip easily.

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🔧 Required Tools

You'll need the following tools for this repair:

• 10mm socket
• 8mm socket
• 1/4-inch ratchet
• 3-inch extension
• Torque wrench inch-pound range
• Flat trim tool
• Needle-nose pliers
• Compressed air duster
• Dielectric grease applicator packet
• Safety glasses
• Nitrile gloves

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🔩 Required Parts

HowToo sells all the parts you need for this repair:

• Ignition coil - Qty: 1-4
• Dielectric grease - Qty: 1 packet

Tip: If one coil failed from age, replacing all four is often best.

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📋 Before You Begin

• 🅿️ Park your Altima on level ground, shift to Park, and set the parking brake.
• ❄️ Let the engine cool for at least 30 minutes.
• 🔋 Use a 10mm socket to loosen the negative battery terminal, then move the cable aside so it cannot touch the battery post.
• 📌 If replacing only one coil, label the bad cylinder location before removing parts.
• 🧰 A torque wrench is a tool that tightens bolts to a measured amount so small bolts do not break or strip.
• 🧴 Dielectric grease is a silicone grease used inside electrical boots to help seal out moisture; use only a tiny amount.

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🔨 Step-by-Step Instructions

Follow these steps in order:

Step 1: Remove the Engine Cover

• Use a 10mm socket and 1/4-inch ratchet to remove the engine cover fasteners if equipped.
• Lift the plastic engine cover straight up and set it aside.
• Keep bolts in a cup.

Step 2: Locate the Ignition Coils

• Look across the top of the engine for four black ignition coils.
• Each coil has one electrical connector and one small mounting bolt.
• Use compressed air duster to blow dirt away from the coil area before removal.

Step 3: Unplug the Coil Connector

• Use your thumb to press the locking tab on the electrical connector.
• If the connector is stuck, use a flat trim tool gently under the connector body.
• Do not pull on the wires.
• If needed, use needle-nose pliers only on the connector housing, not the wiring.

Step 4: Remove the Ignition Coil Bolt

• Use an 8mm socket, 3-inch extension, and 1/4-inch ratchet to remove the coil mounting bolt.
• Set the bolt aside in a safe place.
• Small bolts disappear fast.

Step 5: Remove the Old Ignition Coil

• Grip the top of the coil by hand.
• Twist it slightly left and right to loosen the rubber boot.
• Pull the coil straight upward out of the spark plug tube.
• Check the old coil boot for oil, cracks, carbon tracking, or swelling.
• Carbon tracking means a black lightning-like mark where spark has leaked through the boot.

Step 6: Prepare the New Ignition Coil

• Apply a very small amount of dielectric grease inside the rubber boot using the dielectric grease applicator packet.
• Do not fill the boot with grease.
• Compare the new coil to the old coil before installing it.

Step 7: Install the New Ignition Coil

• Push the new coil straight down into the spark plug tube by hand.
• You should feel the boot seat onto the spark plug.
• Install the coil mounting bolt by hand first to prevent cross-threading.
• Use an 8mm socket, 3-inch extension, and torque wrench to tighten the bolt to 5.4 Nm (48 in-lbs).

Step 8: Reconnect the Coil Connector

• Push the electrical connector onto the ignition coil until it clicks.
• Lightly tug the connector by hand to make sure it is locked.

Step 9: Repeat for Remaining Coils

• If replacing more than one coil, repeat Steps 3 through 8 for each coil.
• Work one coil at a time so connectors do not get mixed up.

Step 10: Reinstall the Engine Cover

• Place the engine cover back into position.
• Use a 10mm socket and 1/4-inch ratchet to reinstall the fasteners if equipped.
• Snug the cover fasteners lightly; do not overtighten plastic parts.

Step 11: Reconnect the Battery

• Place the negative battery cable back onto the battery post.
• Use a 10mm socket and 1/4-inch ratchet to tighten the terminal clamp snugly.
• Make sure the cable does not twist or move by hand.

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✅ After Repair

• ✅ Start the engine and let it idle for 1-2 minutes.
• 👂 Listen for smooth idle. A shaking idle may mean a connector is not fully seated.
• 🚗 Test drive gently for 10-15 minutes.
• 🔍 Recheck that all coil connectors are locked after the test drive.
• 💡 If the check engine light was on before, it may need several drive cycles to turn off, or codes may need clearing with a scan tool.
• ⚠️ If the check engine light flashes, stop driving. A flashing light means active misfire that can damage the catalytic converter.

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💰 DIY vs Shop Cost

Shop Cost: $220-$650 (parts + labor)

DIY Cost: $45-$320 (parts only)

You Save: $175-$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?

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.

🔧 Altima - Ignition Coil Replacement

Replacing the ignition coils on your Altima is a simple top-of-engine repair. The coils send spark to the spark plugs, and a failed coil can cause misfires, rough idle, poor acceleration, or a flashing check engine light.

Difficulty Level: Beginner | Estimated Time: 30-60 minutes

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⚠️ Safety & Precautions

• ⚠️ Let the engine cool before touching the coils or intake area.
• 🔋 Disconnect the negative battery cable before unplugging ignition coils.
• ⚡ Never unplug ignition coils with the engine running because the ignition system can produce high voltage.
• 🧼 Keep dirt out of the spark plug tubes. Blow debris away before removing coils.
• 🔧 Do not overtighten coil bolts. The bolts are small and thread into aluminum.

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🔧 Required Tools

You'll need the following tools for this repair:

• 10mm socket
• 8mm socket
• 1/4-inch ratchet
• 3-inch extension
• Torque wrench inch-pound range
• Flat trim tool
• Compressed air duster
• Safety glasses
• Nitrile gloves

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🔩 Required Parts

HowToo sells all the parts you need for this repair:

• Ignition coil - Qty: 1-4
• Dielectric grease - Qty: 1 packet

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📋 Before You Begin

• 🅿️ Park your Altima on level ground, shift to Park, and set the parking brake.
• ❄️ Let the engine cool for at least 30 minutes.
• 🔋 Use a 10mm socket to loosen the negative battery terminal, then move the cable away from the battery post.
• 📌 If replacing only one coil, work on one coil at a time so the connectors stay in the correct locations.
• 🧰 A torque wrench tightens bolts to a measured amount so they do not loosen or strip.
• 🧴 Dielectric grease is silicone grease used inside the coil boot to help seal out moisture; use only a very small amount.

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🔨 Step-by-Step Instructions

Follow these steps in order:

Step 1: Remove the Engine Cover

• Use a 10mm socket and 1/4-inch ratchet to remove the engine cover fasteners, if equipped.
• Lift the plastic engine cover upward and set it aside.
• Keep bolts in a cup.

Step 2: Find the Ignition Coils

• Look on top of the engine for four black ignition coils in a row.
• Each coil has one electrical connector and one small retaining bolt.
• Use compressed air duster to clean dirt away from the coil area.

Step 3: Unplug One Coil Connector

• Use your thumb to press the locking tab on the coil electrical connector.
• Pull the connector straight back from the coil.
• If it sticks, use a flat trim tool to gently help release the connector body.
• Do not pull on the wires.

Step 4: Remove the Coil Bolt

• Use an 8mm socket, 3-inch extension, and 1/4-inch ratchet to remove the ignition coil bolt.
• Place the bolt somewhere safe.
• Small bolts are easy to lose.

Step 5: Remove the Old Ignition Coil

• Grab the top of the coil by hand.
• Twist the coil slightly left and right to loosen the rubber boot.
• Pull the coil straight up out of the spark plug tube.
• Inspect the old coil boot for oil, cracks, swelling, or black burn-like lines.
• Black burn-like lines are called carbon tracking, which means spark has been leaking through the boot.

Step 6: Prepare the New Coil

• Use the dielectric grease packet to apply a tiny amount inside the rubber boot of the new ignition coil.
• Do not pack the boot full of grease.
• Compare the new coil with the old coil before installing it.

Step 7: Install the New Coil

• Push the new coil straight down into the spark plug tube by hand.
• Press until the boot seats firmly onto the spark plug.
• Start the coil bolt by hand first to avoid cross-threading.
• Use an 8mm socket, 3-inch extension, and torque wrench to tighten the coil bolt to 5.4 Nm (48 in-lbs).

Step 8: Reconnect the Coil Connector

• Push the electrical connector onto the ignition coil until it clicks.
• Gently tug the connector by hand to make sure it is locked in place.

Step 9: Repeat for the Other Coils

• If replacing all coils, repeat Steps 3 through 8 for each remaining coil.
• Use the 8mm socket, 3-inch extension, and torque wrench for each coil bolt.
• Torque each coil bolt to 5.4 Nm (48 in-lbs).

Step 10: Reinstall the Engine Cover

• Set the engine cover back into place.
• Use a 10mm socket and 1/4-inch ratchet to reinstall the engine cover fasteners, if equipped.
• Snug the fasteners lightly because the cover is plastic.

Step 11: Reconnect the Battery

• Place the negative battery cable back onto the battery post.
• Use a 10mm socket and 1/4-inch ratchet to tighten the terminal clamp.
• Make sure the cable does not move by hand.

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✅ After Repair

• ✅ Start the engine and let it idle for 1-2 minutes.
• 👂 Listen for a smooth idle with no shaking.
• 🔍 If the engine runs rough, shut it off and recheck every coil connector.
• 🚗 Take a gentle 10-15 minute test drive.
• 💡 If the check engine light was on, codes may need to be cleared with a scan tool.
• ⚠️ If the check engine light flashes, stop driving because an active misfire can damage the catalytic converter.

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💰 DIY vs Shop Cost

Shop Cost: $220-$650 (parts + labor)

DIY Cost: $45-$320 (parts only)

You Save: $175-$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?

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.