🔧 86 - Ignition Coil Replacement

Your 86 uses coil-on-plug ignition coils (one coil per cylinder) mounted on the sides of the engine. Replacing a weak or failed coil can fix misfires, rough idle, and a flashing check engine light.

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

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⚠️ Safety & Precautions

• ⚠️ Let the engine cool fully; coils sit near hot cylinder heads.
• ⚠️ Disconnect the negative battery terminal to prevent accidental shorting.
• ⚠️ Do not pull on wiring; release connectors by the locking tab.
• ⚠️ If the check engine light was flashing, avoid hard driving until repaired.

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🔧 Required Tools

You'll need the following tools for this repair:

• 10mm socket
• 1/4" drive ratchet
• 6" extension (1/4" drive)
• Torque wrench (inch-pound or low-range Nm)
• Flathead screwdriver
• Trim clip removal tool
• Needle-nose pliers
• Shop light
• Mechanic 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: 1-4 Replace as needed (often best as a set).
• Dielectric grease - Qty: 1 Optional but recommended.

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📋 Before You Begin

• Park on level ground, shift to Park, and set the parking brake.
• Open the hood and let the engine cool completely.
• Use a 10mm socket to disconnect the negative battery terminal and move it aside so it can’t spring back.
• If you have an OBD2 scan tool, pull codes first (for example P0301–P0304) to identify the cylinder.

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🔨 Step-by-Step Instructions

Follow these steps in order:

Step 1: Create working room to reach the coils

• Remove the plastic engine cover by pulling it upward firmly by hand.
• On the passenger side, loosen the intake hose clamp(s) using a flathead screwdriver.
• Unclip/remove the air intake duct/airbox pieces as needed to access the passenger-side coils using a trim clip removal tool and needle-nose pliers (for any hose clamps).
• On the driver side, if access is tight, remove the battery hold-down and shift the battery/nearby ducting aside using a 10mm socket.

Step 2: Unplug the ignition coil electrical connector

• Locate the coil on the side of the engine (one per cylinder).
• Press the connector lock tab, then pull the connector straight off the coil.
• If stuck, wiggle gently—don’t yank wires.

Step 3: Remove the ignition coil retaining bolt

• Use a 10mm socket with a 6" extension and 1/4" drive ratchet to remove the coil hold-down bolt.
• Set the bolt aside where it won’t fall into the engine bay.

Step 4: Remove the ignition coil

• Twist the coil slightly to break the seal, then pull it straight out.
• If the rubber boot stays stuck on the spark plug, pull it out carefully by hand and reinstall it onto the coil.
• Boot = rubber sleeve that grips the plug.

Step 5: Install the new ignition coil

• Optional: apply a tiny smear of dielectric grease inside the boot. Dielectric grease is non-conductive silicone grease that helps prevent moisture and sticking.
• Push the coil straight onto the spark plug until it seats fully.
• Reinstall the hold-down bolt by hand first (to avoid cross-threading), then tighten with a torque wrench: Torque to 7.5 Nm (66 in-lbs).

Step 6: Reconnect the electrical connector

• Push the connector onto the coil until it clicks.
• Give it a gentle tug to confirm it’s locked.

Step 7: Repeat for any other coils being replaced

• Repeat Steps 2–6 for the remaining cylinders if you’re replacing more than one coil.

Step 8: Reinstall removed intake/battery parts

• Reinstall the air intake ducting/airbox components using the trim clip removal tool (for clips) and flathead screwdriver (for clamps).
• If removed, reinstall and secure the battery using a 10mm socket.
• Reconnect the negative battery terminal with a 10mm socket.
• Reinstall the engine cover by pressing it down into place.

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✅ After Repair

• Start the engine and let it idle for 1–2 minutes. It should run smooth with no shaking.
• If you have an OBD2 scan tool, clear the misfire code(s) and confirm they do not return.
• Test drive 10–15 minutes and recheck for a check engine light.
• If the misfire remains, the next likely checks are spark plugs, a coil connector/wiring issue, or fuel injector concerns.

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💰 DIY vs Shop Cost

Shop Cost: ₹4,000-₹18,000 (parts + labor, depending on how many coils)

DIY Cost: ₹2,500-₹14,000 (parts only, depending on how many coils)

You Save: ₹1,500-₹6,000 by doing it yourself!

Shop labor rates vary locally. This repair takes a shop approximately 1.0-2.0 hours.

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🎯 Ready to get started?

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