🔧 4Runner - Ignition Coil Replacement

Your 4Runner uses six individual ignition coils, one above each spark plug. Replacement involves removing the engine cover and intake tube, disconnecting each coil, and installing the new coils without damaging their electrical connectors.

Difficulty Level: Beginner | Estimated Time: 1-1.5 hours

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⚠️ Safety & Precautions

• ⚠️ Let the engine cool completely before touching ignition components.
• 🔋 Disconnect the negative battery terminal to prevent accidental electrical shorts.
• 🚫 Never disconnect an ignition coil while the engine is running; ignition voltage can cause serious injury.
• 🧹 Keep dirt out of the spark-plug wells. Debris can fall into the engine when a spark plug is removed later.
• 🛑 Do not pull on wiring. Release each connector by pressing its locking tab.

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🔧 Required Tools

You'll need the following tools for this repair:

• 10mm socket
• 1/4-inch drive ratchet
• 1/4-inch drive 6-inch extension
• 10mm combination wrench
• Inch-pound torque wrench rated 40-150 in-lbs
• Flat-blade screwdriver with 6mm tip
• Needle-nose pliers with 6-inch jaws
• Compressed-air blow gun with regulated air supply
• Fender cover
• Nitrile mechanic gloves
• Safety glasses

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🔩 Required Parts

HowToo sells all the parts you need for this repair:

• Direct-fit ignition coils - Qty: 6

Ignition coils do not have to be replaced in pairs. If testing identified only one failed coil, replace that coil only; use six if replacing the complete original set.

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📋 Before You Begin

• 🅿️ Park your 4Runner on level ground, select Park, apply the parking brake, and switch the ignition off.
• 🌡️ Allow the engine to become completely cool.
• 🔑 Move the key or keyless remote away from the vehicle.
• 🔋 Record any preferred audio settings, then use a 10mm wrench to loosen and disconnect the negative battery terminal. Isolate the cable so it cannot spring back onto the terminal.
• 🧤 Place a fender cover over the painted bodywork before leaning into the engine compartment.

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🔨 Step-by-Step Instructions

Follow these steps in order:

Step 1: Remove the Engine Appearance Cover

• Use a 10mm socket, extension, and ratchet to remove the cover fasteners, if fitted.
• Lift the front of the plastic engine cover out of its rubber retainers, then remove it from the engine.
• Place the cover where its mounting tabs cannot be broken.

Step 2: Remove the Air-Intake Tube

• Use a 10mm socket and ratchet to loosen the hose clamps at the air-filter housing and throttle body.
• Use needle-nose pliers to release the clamp on the small breather hose, then slide the hose from the intake tube.
• Disconnect any hose or retaining clip attached to the tube. Do not disconnect the mass-airflow sensor unless necessary.
• Work the intake tube free and remove it. Cover the throttle-body opening with a clean, lint-free cloth.
• Photograph hose routing before removal.

Step 3: Clean Around the Ignition Coils

• Put on safety glasses.
• Use a compressed-air blow gun to remove loose dirt from around all six ignition coils.
• Keep the blow gun pointed away from your face and use low, regulated pressure.

Step 4: Disconnect the Coil Connectors

• Press the locking tab on the first ignition-coil connector and pull the connector straight back by its plastic housing.
• If the tab is stiff, use a flat-blade screwdriver gently against the tab. Do not pry against the wires.
• Repeat for the remaining coils that will be replaced.
• A connector lock is the small plastic tab that prevents the plug from vibrating loose.

Step 5: Remove the Old Ignition Coils

• Use a 10mm socket, extension, and ratchet to remove the single retaining bolt from each coil.
• Twist each coil gently to release its rubber boot from the spark plug.
• Pull the coil straight upward and out of the spark-plug well.
• Check the old boot for engine oil or coolant. Fluid inside a well indicates a separate leak that should be repaired before installing the new coil.

Step 6: Inspect the Spark-Plug Wells

• Use a flashlight to verify that every spark-plug well is dry and free of dirt.
• If loose debris is visible, remove it with the compressed-air blow gun while wearing safety glasses.
• Do not remove the spark plugs unless they are also being serviced.

Step 7: Install the New Ignition Coils

• Compare each replacement coil with the removed coil. The electrical socket, mounting tab, boot length, and seal must match.
• Lower each coil straight into its spark-plug well.
• Press down firmly until the rubber boot seats over the spark-plug terminal.
• Start each retaining bolt by hand to prevent crossed threads.
• Use an inch-pound torque wrench with a 10mm socket to tighten each coil bolt to 10 Nm (89 in-lbs).
• Do not apply grease inside the coil boots unless the coil manufacturer specifically supplies or requires it.

Step 8: Reconnect the Electrical Connectors

• Push each connector straight into its ignition coil until the locking tab clicks.
• Gently tug the plastic connector housing to confirm it is locked.
• Check that no wiring is pinched or stretched across a coil.

Step 9: Reinstall the Air-Intake Tube

• Remove the lint-free cloth from the throttle body.
• Fit the intake tube fully onto the throttle body and air-filter housing.
• Reconnect the breather hose and use needle-nose pliers to return its clamp to the original position.
• Reconnect every hose and retaining clip removed earlier.
• Use a 10mm socket and ratchet to tighten the intake clamps until secure. Do not crush the plastic intake fittings.

Step 10: Reinstall the Engine Cover

• Align the engine cover with its rubber retainers and press it evenly into place.
• Install any cover fasteners by hand, then snug them with a 10mm socket and ratchet. These are light-duty cover fasteners; do not overtighten them.

Step 11: Reconnect the Battery

• Place the negative battery cable fully onto the negative terminal.
• Use a 10mm wrench to tighten the terminal until it cannot rotate by hand. Do not overtighten or distort the terminal.

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✅ After Repair

• ✅ Confirm that no tools, cloths, or loose parts remain in the engine compartment.
• 🔊 Start the engine and let it idle. A brief uneven start can occur while the engine computer relearns idle settings after battery disconnection.
• ⚠️ Switch the engine off immediately if it runs severely rough, flashes the check-engine light, or produces arcing or snapping sounds.
• 🔍 If a misfire remains, verify that every coil connector clicked into place and that the intake tube and breather hose are sealed.
• 🚗 Take a short road test under light acceleration, then confirm the check-engine light remains off.
• 🛠️ If a diagnostic trouble code was previously stored, use an appropriate scan tool to clear it only after the underlying fault is repaired.

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💰 DIY vs Shop Cost

Shop Cost: ₹60,000-₹105,000 (six quality coils plus labor)

DIY Cost: ₹45,000-₹90,000 (six quality coils only)

You Save: ₹8,000-₹20,000 by doing it yourself!

Parts pricing in Haryana varies considerably because genuine and premium coils may be imported. This repair takes a shop approximately 0.8-1.2 hours.

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