🔧 F-150 - Spark Plug Replacement

Your F-150 uses coil-on-plug ignition (one ignition coil per cylinder). Replacing the spark plugs restores smooth idle, power, and fuel economy, and helps prevent misfires that can damage the catalytic converters.

Difficulty Level: Intermediate | Estimated Time: 2-4 hours

---

⚠️ Safety & Precautions

• ⚠️ Work on a cold engine to avoid burns and reduce thread damage risk.
• ⚠️ Disconnect the negative battery cable if you’re worried about accidentally shorting a connector.
• ⚠️ Blow dirt out of each spark plug well before removal to prevent debris falling into the cylinder.
• ⚠️ Start spark plugs by hand to avoid cross-threading the aluminum cylinder heads.

---

🔧 Required Tools

You'll need the following tools for this repair:

• Safety glasses
• Nitrile gloves
• 1/4" drive ratchet
• 3/8" drive ratchet
• 7mm socket
• 10mm socket
• 9/16" spark plug socket (rubber insert)
• 3/8" drive extension set (6" and 12")
• 3/8" drive swivel/universal joint
• Torque wrench (inch-pound and foot-pound)
• Compressed air blow gun
• Small flathead screwdriver
• Trim clip tool
• Flashlight

---

🔩 Required Parts

HowToo sells all the parts you need for this repair:

• Spark plugs (Motorcraft correct fit) - Qty: 8
• Dielectric grease - Qty: 1
• Ignition coil boots (recommended if boots are swollen/torn) - Qty: 8

---

📋 Before You Begin

• Park on level ground, shift to Park, and set the parking brake.
• Let the engine cool fully (at least 1-2 hours after driving).
• If disconnecting the battery: use a 10mm socket to remove the negative terminal and keep it from touching the post.
• Label coils if you’re worried about mixing them.

---

🔨 Step-by-Step Instructions

Follow these steps in order:

Step 1: Remove the engine cover (if equipped)

• Use a trim clip tool (or careful hand pull) to release the cover fasteners and lift the cover off.
• Use a flashlight to locate all 8 ignition coils (one per cylinder).

Step 2: Create working room at the front (intake tube)

• Use a flathead screwdriver to loosen the air intake hose clamps if they block access.
• Move the intake tube/ducting aside as needed without forcing it.

Step 3: Unplug one ignition coil

• Use a small flathead screwdriver to gently lift the connector lock tab (if present), then unplug the coil connector.
• Do one cylinder at a time to avoid mix-ups.

Step 4: Remove the coil hold-down bolt and pull the coil out

• Use a 7mm socket to remove the ignition coil bolt.
• Twist the coil slightly by hand, then pull it straight up to remove it from the spark plug well.
• If the rubber boot stays stuck, pull it out gently by hand and plan to replace it.
• Torque to 7 Nm (62 in-lbs) during reassembly.

Step 5: Clean the spark plug well

• Use compressed air blow gun to blow out dirt from around the spark plug.
• This prevents grit from falling into the cylinder when the plug comes out.

Step 6: Remove the spark plug

• Use a 9/16" spark plug socket (rubber insert) with a 3/8" drive extension (6" or 12") and a 3/8" drive swivel/universal joint as needed.
• Turn counterclockwise to remove the plug.
• If it feels unusually tight, stop and work it slowly back-and-forth rather than forcing it.

Step 7: Prep the new spark plug

• Check the gap with your eyes and avoid bending the electrode (most correct-fit plugs come pre-gapped).
• Apply a small dab of dielectric grease inside the coil boot (dielectric grease is a silicone grease that helps prevent moisture and makes future removal easier).
• Do not add anti-seize to the plug threads unless the plug manufacturer specifically requires it.

Step 8: Install the new spark plug (by hand first)

• Place the new plug in the 9/16" spark plug socket and lower it into the well using the extension.
• Thread it in by hand using only the extension (no ratchet at first) until fully seated.
• Use a torque wrench to tighten: Torque to 25 Nm (18 ft-lbs).

Step 9: Reinstall the ignition coil

• Push the coil straight down until you feel it seat on the plug.
• Install the coil bolt using a 7mm socket, then tighten with a torque wrench: Torque to 7 Nm (62 in-lbs).
• Reconnect the electrical connector until it clicks.

Step 10: Repeat for the remaining 7 cylinders

• Repeat Steps 3–9 one cylinder at a time.
• Use the flashlight and swivel for the rear cylinders (they’re tighter to reach).

Step 11: Reassemble and reconnect

• Reinstall the intake tube using a flathead screwdriver to tighten clamps.
• Reinstall the engine cover.
• If disconnected, reconnect the battery negative terminal using a 10mm socket.

---

✅ After Repair

• Start the engine and let it idle for 1-2 minutes. It should run smooth with no flashing check-engine light.
• Listen for a “ticking” sound (can indicate a loose plug) and re-check torque if anything seems off.
• Test drive 10-15 minutes and confirm no misfire or hesitation under light acceleration.

---

💰 DIY vs Shop Cost

Shop Cost: $350-$800 (parts + labor)

DIY Cost: $60-$180 (parts only)

You Save: $290-$620 by doing it yourself!

Shop labor rates vary but typically run $100-$150/hour. This repair takes a shop approximately 2-4 hours.

---

🎯 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.