🔧 Altima - Ignition Coil Replacement

Replacing the ignition coils on your Altima fixes misfires caused by weak or failed coils. The V6 engine has six coils total: three are easy to access on the front bank, and three sit under the upper intake manifold on the rear bank.

Difficulty Level: Intermediate | Estimated Time: 2-4 hours

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⚠️ Safety & Precautions

• ⚠️ Work only on a cool engine. The intake manifold and cylinder heads can burn you if the engine was recently running.
• ⚠️ Disconnect the negative battery cable before starting to avoid electrical shorts.
• ⚠️ Keep dirt, bolts, and tools out of the intake ports when the intake manifold is removed.
• ⚠️ Do not pull on ignition coil wires. Press the connector tab and pull the connector body instead.
• ⚠️ If replacing only one failed coil, match the cylinder location from the diagnostic trouble code before removing parts.

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🔧 Required Tools

You'll need the following tools for this repair:

• 10mm socket
• 12mm socket
• 14mm socket
• 3/8-inch ratchet
• 3/8-inch extension set
• Inch-pound torque wrench
• Foot-pound torque wrench
• Flat-blade screwdriver
• Needle-nose pliers
• Plastic trim tool
• Pick tool
• Shop vacuum
• Clean shop towels
• Masking tape
• Permanent marker
• Nitrile gloves
• Safety glasses

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🔩 Required Parts

HowToo sells all the parts you need for this repair:

• Ignition coil - Qty: 1-6
• Upper intake manifold gasket set - Qty: 1
• Throttle body gasket - Qty: 1

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📋 Before You Begin

• Park your Altima on level ground and set the parking brake.
• Let the engine cool completely before touching intake or ignition parts.
• Open the hood and use a 10mm socket to disconnect the negative battery cable.
• Label hoses and connectors with masking tape and a permanent marker. This helps first-time DIYers avoid mix-ups.
• A torque wrench is a tool that tightens bolts to an exact tightness so parts seal correctly without cracking.
• The intake manifold is the large air chamber on top of the engine that feeds air into the cylinders.

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🔨 Step-by-Step Instructions

Follow these steps in order:

Step 1: Remove the Engine Cover

• Use a 10mm socket to remove the engine cover fasteners, if equipped.
• Lift the cover straight up and set it aside.
• Keep bolts in a cup.

Step 2: Disconnect the Battery

• Use a 10mm socket to loosen the negative battery terminal nut.
• Move the cable away from the battery post so it cannot spring back.

Step 3: Remove the Air Intake Duct

• Use a flat-blade screwdriver to loosen the hose clamp at the throttle body.
• Use a flat-blade screwdriver to loosen the hose clamp at the air cleaner box.
• Use needle-nose pliers to release any small hose clamps attached to the intake duct.
• Pull the air intake duct off and place it aside.

Step 4: Access the Front Ignition Coils

• The front three ignition coils are visible at the front side of the engine.
• Use a plastic trim tool or your thumb to press each coil connector release tab.
• Unplug the connector by pulling the connector body, not the wires.
• Use a 10mm socket to remove each front ignition coil retaining bolt.
• Twist each coil gently by hand, then pull it straight up.

Step 5: Install Front Ignition Coils

• Push each new ignition coil straight into the spark plug tube until it seats fully.
• Use a 10mm socket to install the coil retaining bolt.
• Use an inch-pound torque wrench to tighten each coil bolt to Torque to 5.4 Nm (48 in-lbs).
• Reconnect each ignition coil electrical connector until it clicks.
• A click means it locked.

Step 6: Remove Throttle Body Electrical Connector

• If replacing the rear coils, use a plastic trim tool or your thumb to unlock the throttle body connector.
• Pull the connector straight off by the connector body.
• Do not force the connector. Use a pick tool gently if the locking tab is stuck.

Step 7: Disconnect Hoses and Brackets from the Upper Intake Manifold

• Use masking tape and a permanent marker to label every hose before removal.
• Use needle-nose pliers to release spring clamps on vacuum and breather hoses.
• Use a 10mm socket and 12mm socket to remove brackets attached to the upper intake manifold.
• Move hoses and harnesses aside carefully without stretching them.

Step 8: Remove the Upper Intake Manifold

• Use a 12mm socket, 3/8-inch ratchet, and 3/8-inch extension set to remove the upper intake manifold bolts and nuts.
• Lift the upper intake manifold upward evenly.
• If it sticks, gently work it loose by hand. Do not pry against sealing surfaces with metal tools.
• Remove the old upper intake manifold gasket set.

Step 9: Cover the Intake Ports

• Use a shop vacuum to clean loose dirt from around the intake openings.
• Place clean shop towels into the intake ports so nothing can fall inside.
• Count towels before and after.

Step 10: Remove the Rear Ignition Coils

• Use a plastic trim tool or your thumb to press the connector release tab on each rear ignition coil.
• Unplug each connector by pulling the connector body.
• Use a 10mm socket to remove each rear ignition coil retaining bolt.
• Twist each coil gently by hand, then pull it straight up from the spark plug tube.

Step 11: Install Rear Ignition Coils

• Push each new ignition coil straight down until fully seated.
• Use a 10mm socket to install each coil retaining bolt.
• Use an inch-pound torque wrench to tighten each coil bolt to Torque to 5.4 Nm (48 in-lbs).
• Reconnect each coil connector until it clicks.

Step 12: Reinstall the Upper Intake Manifold

• Remove all clean shop towels from the intake ports. Count them to make sure none are left inside.
• Install the new upper intake manifold gasket set onto the lower intake.
• Set the upper intake manifold carefully into place.
• Use a 12mm socket to start all bolts and nuts by hand first.
• Use an inch-pound torque wrench to tighten the upper intake manifold fasteners in a crisscross pattern to Torque to 18 Nm (13 ft-lbs).

Step 13: Reinstall Throttle Body and Hoses

• If the throttle body was removed, install a new throttle body gasket.
• Use a 10mm socket to install the throttle body bolts.
• Use an inch-pound torque wrench to tighten the throttle body bolts to Torque to 8.4 Nm (74 in-lbs).
• Use needle-nose pliers to reinstall hose clamps on all vacuum and breather hoses.
• Use a 10mm socket and 12mm socket to reinstall any brackets removed earlier.

Step 14: Reinstall the Air Intake Duct

• Slide the intake duct back onto the throttle body and air cleaner box.
• Use a flat-blade screwdriver to tighten both hose clamps snugly.
• Reconnect any small hoses removed from the duct using needle-nose pliers.

Step 15: Reconnect the Battery and Reinstall the Cover

• Use a 10mm socket to reconnect the negative battery cable.
• Use a 10mm socket to reinstall the engine cover fasteners.
• Use a foot-pound torque wrench only if your battery terminal clamp needs final tightening; tighten snugly, not excessively.

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✅ After Repair

• ✅ Turn the key on for 5 seconds before starting. This lets the throttle body initialize.
• ✅ Start the engine and let it idle. It may idle rough for a few seconds while the computer relearns airflow.
• ✅ Listen for hissing sounds around the intake manifold. A hiss can mean a vacuum leak.
• ✅ Check that every ignition coil connector, vacuum hose, and intake duct clamp is fully seated.
• ✅ If the check engine light was on, clear codes with a scan tool after confirming the engine runs smoothly.
• ✅ Test drive gently for 10-15 minutes and confirm the misfire is gone.

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💰 DIY vs Shop Cost

Shop Cost: $450-$1,100 (parts + labor)

DIY Cost: $80-$480 (parts only)

You Save: $370-$620 by doing it yourself!

Shop labor rates vary but typically run $100-$150/hour. This repair takes a shop approximately 2-3 hours.

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