🔧 F-150 - Spark Plug Replacement

On your F-150’s 2.7L EcoBoost, spark plugs wear over time and can cause misfires, rough idle, and poor fuel economy. This job involves removing the ignition coils, swapping the plugs, and torquing everything correctly to protect the aluminum cylinder heads.

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

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⚠️ Safety & Precautions

• ⚠️ Let the engine cool fully; hot aluminum threads strip easily.
• ⚠️ Keep dirt out of the plug holes; debris can damage the engine.
• ⚠️ Disconnect the negative battery cable if you’re worried about accidental shorting while unplugging coils.
• ⚠️ Don’t use anti-seize on modern plated spark plugs unless the plug maker specifically requires it.

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🔧 Required Tools

You'll need the following tools for this repair:

• Safety glasses
• Mechanic gloves
• Ratchet 3/8"
• Torque wrench 3/8" (inch-lb or low Nm capable)
• Socket set metric (7mm, 8mm, 10mm)
• 5/8" spark plug socket (rubber insert or магнит type)
• Extension set 3/8" (3", 6")
• Swivel/universal joint 3/8"
• Small flathead screwdriver
• Compressed air blow gun
• Shop vacuum
• Pickup tool (magnetic) (specialty)
• Flashlight

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🔩 Required Parts

HowToo sells all the parts you need for this repair:

• Spark plugs (OEM-style for 2.7L EcoBoost) - Qty: 6
• 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 completely (best: leave it overnight).
• If disconnecting the battery: use a 10mm socket to remove the negative terminal and move it aside so it can’t spring back.
• Know this term: an ignition coil is the pencil-shaped part that sits on top of each spark plug.

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🔨 Step-by-Step Instructions

Follow these steps in order:

Step 1: Remove the engine cover (if equipped)

• Use your hands to pull up on the cover corners to pop it off the mounting grommets.
• Set it aside where it won’t get stepped on.

Step 2: Unplug and remove ignition coils

• Work one cylinder at a time so parts don’t get mixed up.
• Use a small flathead screwdriver to help lift the electrical connector lock (don’t force it).
• Press the tab and pull the connector straight off the coil.
• Remove the coil hold-down bolt using an 8mm socket (some trucks may use 7mm).
• Twist the coil gently, then pull it straight up and out.
• Tip: A gentle twist breaks the boot’s seal.
• When reinstalling coil bolts later: Torque to 7 Nm (62 in-lb).

Step 3: Clean the spark plug wells

• Use a shop vacuum around the coil opening to remove loose dirt.
• Use compressed air blow gun to blow out the spark plug well (this prevents grit from falling into the cylinder).
• Wear safety glasses—dirt can shoot back out.

Step 4: Remove the old spark plug

• Install the 5/8" spark plug socket on a 6" extension and 3/8" ratchet.
• Lower it straight down onto the plug until you feel it seat.
• Loosen the plug slowly. If it feels stuck, tighten slightly then loosen again.
• Lift the plug out with the socket. If it falls off, use the pickup tool (magnetic) (specialty).

Step 5: Install the new spark plug (start by hand)

• Confirm the new plugs match the old ones (same length and tip style).
• Do not change the gap unless your plug instructions specifically say to; many modern plugs are set from the factory.
• Place the new plug into the 5/8" spark plug socket and lower it into the hole.
• Thread it in by hand using just the extension (no ratchet at first). This prevents cross-threading (when threads go in crooked and ruin the head).
• Once finger-tight, use the torque wrench 3/8" to tighten: Torque to 15 Nm (133 in-lb).

Step 6: Reinstall the ignition coil

• Put a small dab of dielectric grease inside the end of the coil boot. (Dielectric grease is a non-conductive grease that helps sealing and future removal.)
• Push the coil straight down until it fully seats on the plug.
• Install the coil bolt with an 8mm socket, then tighten with a torque wrench: Torque to 7 Nm (62 in-lb).
• Plug the connector back in until it clicks and locks.

Step 7: Repeat for all six cylinders

• Repeat Steps 2–6 for each coil/plug.
• Use the flashlight to confirm every connector is plugged in before you finish.

Step 8: Reinstall engine cover and reconnect battery (if removed)

• Press the engine cover down onto the grommets until it snaps in place.
• If disconnected, reinstall the negative battery cable with a 10mm socket and tighten snugly.

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✅ After Repair

• Start the engine and let it idle for 1–2 minutes. It should run smooth.
• Listen for a ticking/air leak sound near a coil area (often a coil not fully seated).
• If the check engine light comes on or it runs rough, re-check that every coil connector is fully clicked in.
• Test drive 5–10 minutes with light acceleration, then re-check for any warning lights.

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💰 DIY vs Shop Cost

Shop Cost: $250-$500 (parts + labor)

DIY Cost: $45-$120 (parts only)

You Save: $205-$380 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.

Assumption: stock 2.7L EcoBoost ignition system using OEM-style plugs.