🔧 Sedona - Spark Plug Replacement

On your Sedona’s 3.3L V6, the front 3 spark plugs are easy to reach, but the rear 3 sit under the upper intake manifold (the “plenum,” the top part of the intake that feeds air to the engine). Replacing all 6 plugs restores smooth idle, power, and fuel economy, and helps prevent coil damage from worn plugs.

Difficulty Level: Intermediate | Estimated Time: 2.5-4.0 hours

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⚠️ Safety & Precautions

• ⚠️ Work on a fully cool engine to avoid burns and prevent thread damage in the aluminum cylinder heads.
• ⚠️ Disconnect the negative battery cable before unplugging ignition coils and throttle body connectors.
• ⚠️ Keep dirt out of the intake: cover open intake ports with clean shop towels immediately after the plenum comes off.
• ⚠️ Do not over-tighten spark plugs—stripped threads in aluminum heads are expensive to repair.

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🔧 Required Tools

You'll need the following tools for this repair:

• Safety glasses
• Nitrile gloves
• Floor jack (rated 2-ton minimum)
• Jack stands (rated 2-ton minimum)
• Wheel chocks
• 3/8" drive ratchet
• 3/8" drive torque wrench (10-60 ft-lb range)
• 5/8" spark plug socket
• 3/8" drive extension set (3", 6", 10")
• Universal joint adapter (3/8" drive)
• 10mm socket
• 12mm socket
• 14mm socket
• Phillips screwdriver
• Flat screwdriver
• Trim clip removal tool
• Needle-nose pliers
• Magnetic pickup tool
• Compressed air blow gun
• Flashlight
• Shop towels

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🔩 Required Parts

HowToo sells all the parts you need for this repair:

• Spark plugs (iridium/platinum, correct spec for 3.3L V6) - Qty: 6
• Upper intake manifold (plenum) 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.
• Open the hood and remove loose jewelry and hoodie strings.
• Use a 10mm socket to disconnect the negative battery terminal and tuck it aside so it can’t spring back.
• Take photos before unplugging hoses/connectors.

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🔨 Step-by-Step Instructions

Follow these steps in order:

Step 1: Remove the engine cover and intake snorkel

• Pull up to remove the engine cover (it’s held by rubber grommets).
• Use a Phillips screwdriver or flat screwdriver to loosen the intake hose clamps at the air tube.
• Unclip/remove any intake duct fasteners using a trim clip removal tool, then lift the ducting out.

Step 2: Label and disconnect the throttle body/intake connections

• Use needle-nose pliers to slide spring clamps back, then remove small vacuum hoses (twist gently to break them free).
• Unplug electrical connectors by pressing the lock tab and pulling straight off.
• Don’t pull on the wires—pull the connector body.

Step 3: Remove the throttle body (to access plenum hardware)

• Use a 10mm socket to remove the throttle body mounting bolts.
• Remove the throttle body and set it aside on shop towels.
• Remove and discard the old throttle body gasket.
• Torque to 10 Nm (7 ft-lb) on reinstall.
• Tool definition: a throttle body is the valve that controls how much air enters the engine.

Step 4: Remove the upper intake manifold (plenum)

• Use a 10mm socket and 12mm socket (as equipped) with a 3/8" drive ratchet and extensions to remove the plenum bolts/nuts.
• Lift the plenum straight up and out. If it feels stuck, re-check for a hidden bolt or hose before prying.
• Immediately place shop towels into the exposed intake ports so nothing can fall in.
• Remove and discard the old upper intake manifold gaskets.
• Torque to 20 Nm (15 ft-lb) on reinstall.
• Tool definition: the upper intake manifold/plenum is the top air chamber feeding the cylinders.

Step 5: Remove ignition coils (front bank and rear bank)

• Unplug each ignition coil connector by pressing the lock tab.
• Use a 10mm socket to remove each coil hold-down bolt.
• Twist the coil slightly, then pull it straight up and out.
• Torque to 9 Nm (80 in-lb) on reinstall.
• Tool definition: an ignition coil is the part that creates high voltage to fire the spark plug.

Step 6: Clean the spark plug wells

• Use a compressed air blow gun to blow dirt out of each spark plug “well” (the deep tube the plug sits in).
• Use a flashlight to confirm the area is clean before removing plugs.

Step 7: Remove the old spark plugs

• Use a 5/8" spark plug socket with a 3/8" drive ratchet, extensions, and a universal joint adapter as needed.
• Break each plug loose carefully, then spin it out by hand with the socket/extension.
• If a plug feels like it’s binding, stop and work it back-and-forth gently to avoid thread damage.

Step 8: Install the new spark plugs

• Start each plug by hand using the spark plug socket and an extension only (no ratchet at first) so you don’t cross-thread.
• Once finger-tight, tighten with a 3/8" drive torque wrench to 18 Nm (13 ft-lb).
• Apply a tiny amount of dielectric grease inside each coil boot (this helps sealing and future removal).
• Do not re-gap iridium plugs.

Step 9: Reinstall coils and reassemble the intake

• Reinstall the ignition coils and bolts using a 10mm socket, then torque to 9 Nm (80 in-lb).
• Install new upper intake manifold gaskets, then set the plenum back in place.
• Tighten plenum fasteners evenly (crisscross pattern) using a 10mm socket/12mm socket, then torque to 20 Nm (15 ft-lb).
• Reinstall the throttle body with a new gasket using a 10mm socket, then torque to 10 Nm (7 ft-lb).
• Reconnect all vacuum hoses and electrical connectors, and reinstall the intake ducting using a screwdriver.

Step 10: Reconnect the battery and final check

• Reconnect the negative battery terminal using a 10mm socket.
• Visually confirm: no leftover bolts, all connectors clicked in, and no shop towels left in the intake.

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✅ After Repair

• Start the engine and let it idle for 2-3 minutes. It may idle slightly high briefly while the throttle relearns.
• Listen for vacuum leaks (a loud hiss) and watch for a check engine light.
• Road test 10-15 minutes, then recheck for any loose clamps or fuel/air/vacuum smells.
• If it misfires, re-check coil connectors first.

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💰 DIY vs Shop Cost

Shop Cost: $350-$650 (parts + labor)

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

You Save: $170-$590 by doing it yourself!

Shop labor rates vary but typically run $100-$150/hour. This repair takes a shop approximately 2.5-4.0 hours.

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🎯 Ready to get started?

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