🔧 Maxima - Ignition Coil Replacement

Ignition coils sit on top of the spark plugs and create the high voltage that makes the engine run. When a coil gets weak or fails, you’ll usually feel a misfire (shaking, hesitation) and may get a check-engine light.

Difficulty Level: Intermediate | Estimated Time: 0.5-3.0 hours

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⚠️ Safety & Precautions

• ⚠️ Let the engine cool completely before starting (hot intake parts burn).
• ⚠️ Disconnect the negative battery cable to prevent accidental shorts.
• ⚠️ Keep dirt out of the intake—stuff clean rags in any open intake ports.
• ⚠️ Do not pry on plastic electrical connectors; use the release tab.

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🔧 Required Tools

You'll need the following tools for this repair:

• 10mm socket
• 12mm socket
• 1/4" drive ratchet
• 3/8" drive ratchet
• 3" extension
• 6" extension
• Torque wrench (inch-lb range)
• Torque wrench (ft-lb range)
• Flat trim tool
• Needle-nose pliers
• Small pick tool
• Shop rags
• 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 (only if rear coils are replaced)
• Throttle body gasket - Qty: 1 (only if throttle body is removed)
• Dielectric grease - Qty: 1 (optional)

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📋 Before You Begin

• Park on level ground, shift to Park, and set the parking brake.
• Open the hood and remove any loose jewelry/necklaces.
• Disconnect the battery: use a 10mm socket to remove the negative terminal and tuck it aside so it can’t spring back.
• If you’re only doing the front bank coils (radiator side), you usually won’t need to remove the intake plenum.
• If you’re doing the rear bank coils (firewall side), plan on removing the upper intake manifold (plenum) and replacing its gaskets.

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🔨 Step-by-Step Instructions

Follow these steps in order:

Step 1: Remove the engine cover

• Pull up on the plastic engine cover to pop it off the rubber grommets (use a flat trim tool if it’s stubborn).

Step 2: Identify which coils you’re replacing

• The front bank coils are closest to the radiator and are the easiest to access.
• The rear bank coils are closest to the firewall and are under the upper intake manifold (plenum).
• If you have a misfire code, replace that cylinder’s coil first.

Step 3: Replace a front bank coil (radiator side)

• Unplug the coil connector: press the tab, then pull straight back (use a small pick tool gently if the tab is stuck).
• Remove the coil retaining bolt with a 10mm socket.
• Twist the coil boot slightly, then pull the coil straight up and out.
• Add a tiny smear of dielectric grease inside the new coil boot (optional).
• Install the new coil straight down until it fully seats on the spark plug.
• Install the retaining bolt with a 10mm socket and Torque to 7.2 Nm (64 in-lb).
• Reconnect the electrical connector until it clicks.

Step 4: If replacing rear bank coils, remove the air intake duct

• Loosen the intake duct clamps using a flat trim tool or hand screwdriver-style ratchet technique with a 10mm socket (depending on clamp type).
• Unplug the intake/MAF connector(s) by pressing the lock tab and pulling back.
• Remove the ducting and set it aside.

Step 5: Remove the upper intake manifold (plenum) to access rear coils

• Label vacuum hoses/connectors with tape so they go back to the same spot.
• Disconnect vacuum hoses using needle-nose pliers for spring clamps.
• Remove plenum mounting bolts/nuts using a 12mm socket and extensions.
• Lift the plenum straight up and off.
• Immediately stuff clean shop rags into the exposed intake ports.
• Remove and discard the old plenum gaskets.

Step 6: Replace rear bank coils (firewall side)

• Repeat the same coil steps as the front bank: unplug connector, remove bolt with 10mm socket, twist and pull coil out, install new coil.
• Install each coil retaining bolt and Torque to 7.2 Nm (64 in-lb).
• Reconnect each coil connector until it clicks.

Step 7: Reinstall the upper intake manifold (plenum)

• Remove the shop rags from the intake ports.
• Install new upper intake manifold gaskets in the correct grooves.
• Set the plenum back in place carefully without pinching hoses/wiring.
• Start all bolts/nuts by hand first to avoid cross-threading.
• Tighten plenum bolts/nuts using a 12mm socket, then Torque to 25 Nm (18 ft-lb).
• Reconnect all hoses and electrical connectors.

Step 8: Reinstall the intake duct and engine cover

• Reinstall the intake ducting and tighten clamps using a 10mm socket.
• Reconnect the MAF/intake connector(s) until they click.
• Press the engine cover back onto the mounting grommets.

Step 9: Reconnect the battery

• Reconnect the negative battery cable using a 10mm socket.

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✅ After Repair

• Start your Maxima and let it idle for 1-2 minutes. It should run smooth with no shaking.
• Listen for hissing (vacuum leak) around the plenum area if you removed it.
• If the check-engine light stays on, the code may need to be cleared after the repair.
• Take a short test drive and re-check for any new warning lights.

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💰 DIY vs Shop Cost

Shop Cost: $350-$950 (parts + labor)

DIY Cost: $60-$480 (parts only)

You Save: $290-$470 by doing it yourself!

Shop labor rates vary but typically run $100-$150/hour. This repair takes a shop approximately 1.0-2.5 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.