🔧 Tacoma - Spark Plug Replacement

Replacing the spark plugs on your Tacoma helps restore smooth starting, steady idle, fuel economy, and proper ignition performance. The 3.5L V6 uses six spark plugs and coil-on-plug ignition, meaning each plug has its own ignition coil mounted directly above it.

Difficulty Level: Intermediate | Estimated Time: 2.5-4 hours

---

⚠️ Safety & Precautions

• ⚠️ Work only on a completely cool engine to avoid burns and damaged aluminum threads.
• ⚠️ Disconnect the negative battery cable before unplugging ignition coils.
• ⚠️ Blow dirt away from each spark plug well before removal so debris does not fall into the engine.
• ⚠️ Start each new spark plug by hand first. Cross-threading the aluminum cylinder head is expensive to repair.
• ⚠️ Do not use anti-seize unless the spark plug maker specifically requires it; most modern iridium plugs come with coated threads.

---

🔧 Required Tools

You'll need the following tools for this repair:

• 10mm socket
• 12mm socket
• 14mm thin-wall spark plug socket with rubber insert
• 3/8-inch ratchet
• 3/8-inch torque wrench
• 3-inch extension
• 6-inch extension
• 3/8-inch universal joint adapter
• Needle-nose pliers
• Flat-blade screwdriver
• Plastic trim clip removal tool
• Compressed air nozzle
• Spark plug gap gauge
• Dielectric grease applicator brush
• Fender cover
• Nitrile gloves
• Safety glasses

---

🔩 Required Parts

HowToo sells all the parts you need for this repair:

• Iridium spark plugs - Qty: 6
• Dielectric grease - Qty: 1 small tube
• Throttle body gasket - Qty: 1
• Intake air tube clamp if damaged - Qty: As needed

---

📋 Before You Begin

• Park your Tacoma on level ground, shift to Park, and set the parking brake.
• Let the engine cool fully. Cool metal is safer and protects the cylinder head threads.
• Use a fender cover to protect paint while leaning into the engine bay.
• Use a 10mm socket to disconnect the negative battery cable, then position it so it cannot spring back to the battery post.
• A universal joint adapter lets the socket bend slightly, which helps reach the rear plugs near the firewall.
• A spark plug gap gauge checks the distance between the center and side electrodes. Do not force-adjust iridium plug tips.

---

🔨 Step-by-Step Instructions

Follow these steps in order:

Step 1: Remove the Engine Cover

• Use your hands to lift the plastic engine cover upward from its rubber mounting grommets.
• Set the cover aside where it will not get scratched or stepped on.
• Pull straight up, not sideways.

Step 2: Disconnect the Negative Battery Cable

• Use a 10mm socket to loosen the negative battery terminal nut.
• Lift the cable off the battery post and move it aside.
• This prevents accidental electrical shorts while unplugging ignition coils.

Step 3: Remove the Air Intake Tube

• Use a flat-blade screwdriver to loosen the intake tube clamp at the air filter box.
• Use a flat-blade screwdriver to loosen the intake tube clamp at the throttle body.
• Use needle-nose pliers to release any small hose clamps attached to the intake tube.
• Carefully unplug any attached electrical connector by pressing the lock tab and pulling straight back.
• Lift the air intake tube out of the engine bay.

Step 4: Remove the Throttle Body for Access

• Use a 10mm socket to remove the throttle body mounting bolts.
• Gently move the throttle body aside without stretching the wiring harness.
• Remove the old throttle body gasket by hand.
• Do not force the throttle plate open with your fingers.
• On installation later, tighten the throttle body bolts evenly to Torque to 10 Nm (89 in-lbs).

Step 5: Clear Access to the Ignition Coils

• Use a 10mm socket to remove small brackets or harness retainers blocking the ignition coils.
• Use a plastic trim clip removal tool to release plastic wiring clips without breaking them.
• Move wiring gently to the side, but do not pull hard on the harness.
• Take phone photos before moving clips.

Step 6: Remove One Ignition Coil at a Time

• Press the lock tab on the first ignition coil connector and unplug it by hand.
• Use a 10mm socket to remove the ignition coil hold-down bolt.
• Twist the ignition coil gently by hand, then pull it straight upward.
• Keep each coil near its original cylinder location.
• On installation later, tighten each ignition coil bolt to Torque to 8 Nm (71 in-lbs).

Step 7: Blow Out the Spark Plug Well

• Put on safety glasses before using compressed air.
• Use a compressed air nozzle to blow dirt and grit out of the spark plug well.
• This is important because loose dirt can fall into the cylinder when the spark plug is removed.

Step 8: Remove the Old Spark Plug

• Use a 14mm thin-wall spark plug socket with a 6-inch extension and 3/8-inch ratchet to loosen the spark plug.
• For rear plugs, use the 3/8-inch universal joint adapter with the 3-inch extension if you need more angle.
• Turn counterclockwise slowly until the plug is free.
• Lift the spark plug out with the socket.
• If the plug feels stuck, stop and tighten slightly, then loosen again slowly.

Step 9: Check the New Spark Plug

• Use a spark plug gap gauge to lightly verify the gap is approximately 0.044 inch.
• Do not pry aggressively on iridium spark plugs because the fine electrode can be damaged.
• Make sure the new spark plug is clean and not dropped or cracked.

Step 10: Install the New Spark Plug by Hand

• Place the new spark plug into the 14mm thin-wall spark plug socket.
• Use the extension by hand only at first, with no ratchet attached.
• Turn clockwise gently until the plug seats by hand.
• If it does not turn smoothly, remove it and start again.
• Hand-starting prevents ruined threads.

Step 11: Torque the New Spark Plug

• Attach the 3/8-inch torque wrench to the extension and spark plug socket.
• Tighten the spark plug to Torque to 18 Nm (13 ft-lbs).
• Do not over-tighten. The cylinder head is aluminum.

Step 12: Reinstall the Ignition Coil

• Apply a small amount of dielectric grease inside the rubber coil boot using a dielectric grease applicator brush.
• Dielectric grease is a non-conductive silicone grease that helps seal moisture out of electrical boots.
• Push the ignition coil straight down over the spark plug until it seats fully.
• Use a 10mm socket to install the coil bolt.
• Use a 3/8-inch torque wrench to tighten the coil bolt to Torque to 8 Nm (71 in-lbs).
• Reconnect the coil electrical connector until it clicks.

Step 13: Repeat for the Remaining Five Spark Plugs

• Repeat Steps 6 through 12 for each remaining cylinder.
• Work on only one spark plug and coil at a time.
• Use the 3-inch extension, 6-inch extension, and universal joint adapter as needed for the rear cylinders.
• Keep wiring and hoses gently moved aside while working near the firewall.

Step 14: Reinstall the Throttle Body

• Place the new throttle body gasket onto the mounting surface by hand.
• Position the throttle body carefully without pinching the gasket.
• Use a 10mm socket to install the throttle body bolts finger-tight first.
• Use a 3/8-inch torque wrench to tighten the bolts evenly to Torque to 10 Nm (89 in-lbs).

Step 15: Reinstall the Air Intake Tube

• Place the air intake tube back between the air filter box and throttle body.
• Use a flat-blade screwdriver to tighten both intake tube clamps snugly.
• Use needle-nose pliers to reinstall any hose clamps.
• Reconnect any electrical connector until it clicks.
• Check that the tube is fully seated and not folded at either end.

Step 16: Reinstall Brackets, Clips, and Engine Cover

• Use a 10mm socket to reinstall any brackets or harness retainers removed earlier.
• Use a plastic trim clip removal tool by hand to guide clips back into place if needed.
• Press the engine cover straight down onto its rubber grommets.

Step 17: Reconnect the Battery

• Place the negative battery cable back onto the battery post.
• Use a 10mm socket to tighten the terminal nut until snug.
• Do not overtighten the battery terminal.

---

✅ After Repair

• Start your Tacoma and let it idle for a few minutes.
• The idle may be slightly uneven at first while the throttle body relearns after battery disconnect.
• Listen for hissing sounds that could indicate a loose intake tube or vacuum leak.
• Check that no warning lights remain on after a short drive.
• Take a gentle 10-15 minute test drive and confirm smooth acceleration.
• If the engine misfires, shut it off and recheck coil connectors, coil seating, and intake tube fitment.

---

💰 DIY vs Shop Cost

Shop Cost: $450-$800 parts + labor

DIY Cost: $70-$180 parts only

You Save: $300-$620 by doing it yourself!

Shop labor rates vary but typically run $100-$150/hour. This repair takes a shop approximately 2-3 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.