🔧 Expedition - Ignition Coil Replacement

Replacing an ignition coil on your Expedition means removing the coil from the top of the spark plug and installing a new one. A bad coil can cause misfires, rough idle, flashing check engine light, poor fuel economy, or loss of power.

Difficulty Level: Beginner to Intermediate | Estimated Time: 1-2 hours

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⚠️ Safety & Precautions

• ⚠️ Let the engine cool completely before working. The turbocharged 3.5L engine can stay hot for a long time.
• ⚠️ Disconnect the negative battery cable before unplugging ignition coils to reduce the chance of electrical shorts.
• ⚠️ Work carefully around the plastic coil connectors. They can become brittle with age.
• ⚠️ Do not pull on the wiring harness. Always release the connector lock first.
• ⚠️ If the check engine light was flashing, avoid driving until the misfire is fixed because raw fuel can damage the catalytic converters.

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🔧 Required Tools

You'll need the following tools for this repair:

• 8mm socket
• 10mm socket
• 1/4-inch ratchet
• 3/8-inch ratchet
• 6-inch extension
• Flat trim tool
• Small flathead screwdriver
• Torque wrench inch-pound range
• OBD2 scan tool
• Dielectric grease packet
• Shop towels
• Nitrile gloves
• Safety glasses

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🔩 Required Parts

HowToo sells all the parts you need for this repair:

• Ignition coil - Qty: 1 per failed cylinder
• Ignition coil set - Qty: 1 if replacing all six
• Spark plugs - Qty: 6 if misfire mileage is high or plugs are worn
• Dielectric grease - Qty: 1 packet

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📋 Before You Begin

• Park your Expedition on level ground, shift to Park, and set the parking brake.
• Open the hood and allow the engine to cool fully.
• Use an OBD2 scan tool to read misfire codes before removing parts. Codes P0301-P0306 identify which cylinder is misfiring.
• Beginner note: an OBD2 scan tool plugs into the diagnostic port under the dash and reads trouble codes from the vehicle computer.
• Cylinder layout on the 3.5L EcoBoost: Bank 1 is passenger side, cylinders 1-2-3 front to rear. Bank 2 is driver side, cylinders 4-5-6 front to rear.
• Use a 10mm socket to disconnect the negative battery cable. Move the cable aside so it cannot spring back onto the battery post.

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🔨 Step-by-Step Instructions

Follow these steps in order:

Step 1: Remove the Engine Appearance Cover

• Put on safety glasses and nitrile gloves.
• Grip the plastic engine cover with both hands and lift upward evenly.
• If it feels stuck, use a flat trim tool gently near the rubber grommet areas.
• Set the cover aside where it will not be stepped on.
• Tip: Pull straight up, not sideways.

Step 2: Locate the Ignition Coils

• The ignition coils sit on top of the valve covers, one coil per cylinder.
• Beginner note: an ignition coil turns low battery voltage into the high voltage needed to fire the spark plug.
• Use your misfire code to choose the correct coil. Example: P0302 points to cylinder 2, passenger side middle coil.
• Use shop towels to wipe loose dirt away from the coil area before removal.

Step 3: Disconnect the Ignition Coil Connector

• Use a small flathead screwdriver to gently lift or release the connector lock tab, if equipped.
• Press the connector release with your finger and pull the connector straight off the coil.
• Do not pull on the wires. Pull only on the plastic connector body.
• If the connector is tight, wiggle it gently while pressing the release tab.
• Tip: Take a photo before unplugging.

Step 4: Remove the Ignition Coil Bolt

• Use an 8mm socket, 1/4-inch ratchet, and 6-inch extension to remove the coil retaining bolt.
• Keep the bolt in a safe place. It is small and easy to drop.
• If access is tight, use the 1/4-inch ratchet instead of the larger ratchet for better control.

Step 5: Remove the Old Ignition Coil

• Hold the coil body and twist it gently left and right to loosen the rubber boot from the spark plug.
• Pull the coil straight upward out of the spark plug well.
• Beginner note: the spark plug well is the deep tube where the spark plug sits.
• Inspect the coil boot for oil, coolant, carbon tracking, cracking, or burning.
• If oil is inside the spark plug well, the valve cover seal may also need repair.

Step 6: Prepare the New Ignition Coil

• Compare the new ignition coil to the old one. The connector shape, mounting tab, and boot length should match.
• Apply a very small amount of dielectric grease packet inside the end of the rubber boot only.
• Beginner note: dielectric grease helps seal out moisture but does not go on the metal electrical contact.
• Do not pack the boot full of grease. Too much can prevent the coil from seating correctly.

Step 7: Install the New Ignition Coil

• Push the new ignition coil straight down into the spark plug well by hand.
• You should feel the boot seat onto the spark plug.
• Align the coil mounting tab with the bolt hole.
• Start the bolt by hand first to avoid cross-threading.
• Use an 8mm socket and torque wrench inch-pound range to tighten the coil bolt to Torque to 6 Nm (53 in-lbs).
• Tip: Snug is enough on small bolts.

Step 8: Reconnect the Coil Connector

• Push the electrical connector onto the ignition coil until it clicks.
• If equipped, use your fingers to slide the red or gray connector lock back into place.
• Gently tug on the connector body to confirm it is locked.

Step 9: Repeat for Additional Coils

• If replacing all six coils, repeat Steps 3-8 for each cylinder.
• Use an 8mm socket, 1/4-inch ratchet, and 6-inch extension for each coil bolt.
• Work one coil at a time so connectors do not get mixed up.
• Each ignition coil bolt should be tightened to Torque to 6 Nm (53 in-lbs).

Step 10: Reinstall the Engine Cover and Battery Cable

• Line up the engine cover with its rubber mounting points.
• Press down firmly by hand until the cover seats.
• Use a 10mm socket and 3/8-inch ratchet to reconnect the negative battery cable.
• Tighten the negative battery terminal until secure. Do not overtighten.

Step 11: Clear Codes and Test Run

• Use an OBD2 scan tool to clear the misfire code after the repair.
• Start the engine and let it idle for 2-3 minutes.
• Listen for smooth idle and check that the check engine light does not return.
• If the engine still misfires, stop and recheck the connector, coil seating, and spark plug condition.

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✅ After Repair

• Drive your Expedition gently for 10-15 minutes and confirm acceleration is smooth.
• Use the OBD2 scan tool again after the test drive to check for pending misfire codes.
• If a misfire moves to a different cylinder after swapping coils, the coil is usually the cause.
• If the same cylinder still misfires with a new coil, inspect the spark plug, injector, wiring, and compression.
• Recheck that all coil connectors are fully clicked into place.

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💰 DIY vs Shop Cost

Shop Cost: $180-$650 depending on whether one coil or all six are replaced

DIY Cost: $45-$350 depending on coil quantity and brand

You Save: $135-$300 by doing it yourself!

Shop labor rates vary but typically run $100-$150/hour. This repair takes a shop approximately 0.5-1.5 hours.

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