🔧 4Runner - Ignition Coil Replacement

Your 4Runner uses one ignition coil per cylinder (6 total). A weak or failed coil can cause misfires, rough running, flashing check-engine light, and poor fuel economy.

Difficulty Level: Beginner | Estimated Time: 1.0-2.0 hours

Assumption: replacing all 6 coils on a stock engine.

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⚠️ Safety & Precautions

• ⚠️ Work on a cool engine; hot parts can burn you.
• ⚠️ If the check-engine light is flashing, avoid driving; misfires can damage the catalytic converters.
• 🔋 Disconnect the negative battery cable to prevent accidental shorts.
• 🧴 Keep oil/cleaners off electrical connectors and coil boots.

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🔧 Required Tools

You'll need the following tools for this repair:

• 10mm socket
• 1/4" drive ratchet
• 3" extension (1/4" drive)
• 6" extension (1/4" drive)
• Torque wrench (inch-pound)
• Flat trim tool
• Pick tool
• Shop light
• Nitrile gloves
• Safety glasses

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🔩 Required Parts

HowToo sells all the parts you need for this repair:

• Ignition coil - Qty: 6
• Dielectric grease - Qty: 1
• Electrical contact cleaner - Qty: 1

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📋 Before You Begin

• Park on level ground and set the parking brake.
• Open the hood and let the engine fully cool.
• Use a 10mm socket to disconnect the negative battery cable and move it aside so it can’t spring back.
• Take a quick photo of each connector location.

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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 cover fasteners.
• Lift the cover off and set it aside.

Step 2: Unplug one ignition coil connector

• Pick one coil to start with (doing one at a time prevents mix-ups).
• Press the connector lock tab and pull the connector straight off.
• If it’s stuck, use a pick tool gently on the tab. (A pick tool is a small hooked tool used to lift clips.)
• Don’t pull on the wires.

Step 3: Remove the coil hold-down bolt

• Use a 10mm socket, 1/4" drive ratchet, and a 3" or 6" extension to remove the single bolt holding the coil.

Step 4: Remove the ignition coil

• Twist the coil slightly, then pull straight up to remove it from the spark plug tube.
• If there’s dirt around the opening, wipe it away before installing the new coil.

Step 5: Prep and install the new coil

• Optional: Spray a small amount of electrical contact cleaner on the connector and let it dry.
• Apply a tiny smear of dielectric grease inside the new coil boot. (Dielectric grease helps seal out moisture and eases future removal.)
• Push the coil straight down until it fully seats.

Step 6: Reinstall the coil bolt and torque it

• Start the bolt by hand to avoid cross-threading.
• Use a 10mm socket to snug it down.
• Use a torque wrench (inch-pound) and tighten the coil bolt to Torque to 9 Nm (80 in-lbs).

Step 7: Reconnect the coil electrical connector

• Push the connector on until it clicks.
• Lightly tug it to confirm it’s locked.

Step 8: Repeat for the remaining coils

• Repeat Steps 2–7 for each cylinder until all coils are replaced.
• Use a shop light to confirm every connector is plugged in and every bolt is installed.

Step 9: Reinstall engine cover and reconnect battery

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

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✅ After Repair

• Start the engine and let it idle for 1–2 minutes. It should run smooth.
• If you have a scan tool, clear any stored misfire codes and recheck for codes after a short test drive.
• Do a 10–15 minute drive, then recheck that the engine is running smoothly and the check-engine light stays off.
• If it still misfires, the spark plugs or wiring may be the cause.

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💰 DIY vs Shop Cost

Shop Cost: $450-$900 (parts + labor)

DIY Cost: $180-$480 (parts only)

You Save: $270-$420 by doing it yourself!

Shop labor rates vary but typically run $100-$150/hour. This repair takes a shop approximately 1.0-2.0 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.