🔧 QX80 - Ignition Coil Replacement

Replacing the ignition coils restores strong spark to the spark plugs and fixes common symptoms like misfires, rough idle, flashing check engine light, or lack of power. On your QX80, each cylinder has its own coil mounted on top of the valve cover, so the job is mostly careful unplug-and-bolt work.

Difficulty Level: Intermediate | Estimated Time: 1.0-2.5 hours

Assumption: Stock intake/engine cover; coil-on-plug setup.

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⚠️ Safety & Precautions

• ⚠️ Let the engine cool fully; coils sit near hot metal.
• ⚠️ Disconnect the negative battery cable to prevent accidental shorts.
• ⚠️ Pull on connectors by the plug body, not the wires.
• ⚠️ Keep dirt out of the spark plug wells; blow them out before removing coils.

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🔧 Required Tools

You'll need the following tools for this repair:

• 10mm socket
• 1/4" drive ratchet
• 6" 1/4" drive extension
• Torque wrench (in-lb or low-range Nm)
• Flat trim tool
• Needle-nose pliers
• Compressed air blow gun
• Shop rags
• Nitrile gloves
• Safety glasses
• OBD2 scan tool

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🔩 Required Parts

HowToo sells all the parts you need for this repair:

• Ignition coil - Qty: 1-8
• Dielectric grease - Qty: 1
• Anti-seize compound - Qty: 1
• Upper intake air duct clamps - Qty: 0-2

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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 or dangling clothing.
• Use a 10mm socket to disconnect the negative battery terminal and tuck it aside so it can’t spring back.
• If you’re replacing multiple coils, label each connector with tape so everything goes back to the same cylinder.

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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 release it from its rubber grommets (mounting bushings).
• Use a flat trim tool if you need gentle leverage at the corners.

Step 2: Create working space (as needed)

• If a coil is blocked by the intake duct, loosen the duct clamps using a 10mm socket and move the duct aside.
• Place a shop rag in any open duct temporarily to prevent debris entry.

Step 3: Unplug the coil electrical connector

• Press the connector lock tab and pull the plug straight back.
• If it’s stubborn, use needle-nose pliers gently on the connector body (not the wires).
• Tip: Wiggle slightly while pulling.

Step 4: Remove the coil hold-down bolt

• Use a 10mm socket, 1/4" drive ratchet, and 6" 1/4" drive extension to remove the coil bolt.
• Set the bolt somewhere safe; they are easy to lose.

Step 5: Remove the ignition coil

• Before pulling the coil, use the compressed air blow gun to blow dirt out of the spark plug well.
• Twist the coil slightly, then pull straight upward to remove it.
• Tip: Don’t pry on the valve cover.

Step 6: Prep and install the new coil

• Put a pea-size amount of dielectric grease inside the new coil boot (the rubber end). Dielectric grease helps prevent moisture and eases future removal.
• Lower the coil straight down until you feel it seat on the spark plug.
• Install the hold-down bolt by hand first to avoid cross-threading.
• Use a torque wrench to tighten the coil bolt: Torque to 8.7 Nm (77 in-lb).

Step 7: Reconnect the coil connector

• Push the connector on until it clicks and locks.
• Do a gentle tug test to confirm it’s fully latched.

Step 8: Repeat for remaining coils

• Work one cylinder at a time so connectors and bolts don’t get mixed up.

Step 9: Reinstall intake ducting and engine cover

• Reposition any intake ducting and tighten clamps using a 10mm socket.
• Press the engine cover back onto its grommets until fully seated.

Step 10: Reconnect the battery

• Use a 10mm socket to reconnect the negative battery terminal snugly.

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✅ After Repair

• Start the engine and let it idle for 1-2 minutes; it should run smooth with no shaking.
• Use an OBD2 scan tool to clear misfire codes and confirm none return.
• Test drive 10-15 minutes with light acceleration, then recheck for warning lights.
• If a misfire remains, re-check that every connector is fully clicked in and each coil is seated.

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💰 DIY vs Shop Cost

Shop Cost: $450-$1,400 (parts + labor, depending on how many coils)

DIY Cost: $60-$800 (parts only, depending on how many coils)

You Save: $300-$600+ 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.