🔧 Explorer - Ignition Coil Replacement

Your Explorer uses coil-on-plug ignition coils—one coil per spark plug. Replacing a bad coil can fix misfires, rough idle, flashing check engine light, and loss of power. On the 3.5L, the front bank is easy, but the rear bank typically requires removing the upper intake manifold to reach the coils.

Difficulty Level: Intermediate | Estimated Time: 1.5-3.0 hours

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⚠️ Safety & Precautions

• ⚠️ Work on a cool engine to avoid burns.
• ⚠️ Disconnect the negative battery cable before unplugging throttle body/engine sensors.
• ⚠️ Keep dirt out of the intake—cover openings with a clean rag.
• ⚠️ Do not pull on wiring; release connector locks first.

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🔧 Required Tools

You'll need the following tools for this repair:

• 10mm socket
• 8mm socket
• 7mm socket
• 1/4" drive ratchet
• 3/8" drive ratchet
• 3" socket extension
• 6" socket extension
• Torque wrench (in-lb or Nm capable)
• Flat-blade screwdriver
• Trim clip removal tool
• Needle-nose pliers
• Marker tape
• Shop rags
• Nitrile gloves
• Safety glasses

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🔩 Required Parts

HowToo sells all the parts you need for this repair:

• Ignition coil - Replace in sets or at least in pairs - Qty: 1-6
• Upper intake manifold gasket set - Qty: 1
• Throttle body gasket - Qty: 1
• Dielectric grease - Qty: 1

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📋 Before You Begin

• 🧰 Park on level ground, shift to Park, and set the parking brake.
• 🧊 Let the engine cool fully.
• 🔋 Disconnect the negative battery cable using a 10mm socket, and isolate it so it can’t spring back.
• 🏷️ Use marker tape to label any hoses/connectors you remove so they go back to the same place.

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🔨 Step-by-Step Instructions

Follow these steps in order:

Step 1: Remove the engine cover

• Pull up on the engine cover to release the grommets (use a trim clip removal tool if needed).
• Set it aside.

Step 2: Remove the air intake duct (to access the throttle body/upper intake)

• Loosen the hose clamps using a 7mm socket (or flat-blade screwdriver, if your clamp style fits).
• Unplug any intake tube sensor connector by releasing the lock and pulling straight off.
• Lift the intake duct out.

Step 3: Disconnect the throttle body connector and attached hoses

• Unplug the throttle body electrical connector (press the lock tab, then pull).
• Remove any small vacuum/PCV hoses connected to the upper intake using needle-nose pliers as needed.
• Tip: Twist hoses gently to break the seal.

Step 4: Remove the throttle body (if it blocks upper intake removal)

• Remove the throttle body mounting bolts using an 8mm socket.
• Remove the throttle body and old gasket. Install the new throttle body gasket during reassembly.
• Reinstall throttle body bolts later and Torque to 10 Nm (89 in-lbs).

Step 5: Remove the upper intake manifold (rear bank access)

• Disconnect remaining electrical connectors and vacuum/EVAP lines attached to the upper intake. Use marker tape to label them.
• Remove the upper intake manifold bolts using an 8mm socket with a 6" socket extension.
• Lift the upper intake manifold straight up and out.
• Immediately cover the intake ports with shop rags so nothing can fall in.
• During reassembly, install the new upper intake manifold gasket set and Torque to 10 Nm (89 in-lbs) (tighten evenly).

Step 6: Remove the ignition coil(s)

• Pick the coil you’re replacing (front bank is now open; rear bank is accessible with the upper intake removed).
• Unplug the coil electrical connector (release the lock tab first).
• Remove the coil hold-down bolt using a 8mm socket.
• Twist the coil boot slightly, then pull the coil straight up and out.

Step 7: Install the new ignition coil(s)

• Apply a small amount of dielectric grease inside the end of the coil boot. (This helps prevent moisture and makes future removal easier.)
• Push the coil straight down onto the spark plug until fully seated.
• Install the hold-down bolt using an 8mm socket and Torque to 10 Nm (89 in-lbs).
• Reconnect the electrical connector until it clicks.
• Repeat for any other coils you’re replacing.

Step 8: Reinstall the upper intake manifold and throttle body

• Remove the shop rags from the intake ports.
• Set the upper intake manifold in place with the new gaskets installed.
• Install bolts finger-tight, then tighten evenly with an 8mm socket and Torque to 10 Nm (89 in-lbs).
• Reinstall the throttle body with a new gasket using an 8mm socket and Torque to 10 Nm (89 in-lbs).
• Reconnect all hoses and electrical connectors (match your labels).

Step 9: Reinstall the air intake duct and engine cover

• Reinstall the intake duct and tighten clamps using a 7mm socket.
• Reconnect any intake duct sensor connector.
• Press the engine cover back onto its grommets.
• Reconnect the negative battery cable using a 10mm socket.

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✅ After Repair

• ✅ Start the engine and let it idle for 2-3 minutes.
• ✅ Listen for hissing (vacuum leak) and watch for a check engine light.
• ✅ Test drive 10-15 minutes and verify the misfire is gone.
• ✅ If the check engine light was on, clear codes with a scan tool, or it may clear after a few drive cycles if the issue is fixed.

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💰 DIY vs Shop Cost

Shop Cost: $350-$900 (parts + labor)

DIY Cost: $60-$450 (parts only)

You Save: $290-$450 by doing it yourself!

Shop labor rates vary but typically run $100-$150/hour. This repair takes a shop approximately 1.5-3.0 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.