🔧 Impala - Ignition Coil Replacement

Your Impala has six individual ignition coils, one above each spark plug. The front three are easy to reach, while replacing the rear three requires removing the upper intake manifold.

Difficulty Level: Intermediate | Estimated Time: 1.5-2.5 hours

Assumption: This procedure replaces all six coils on the stock 3.6L V6.

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⚠️ Safety & Precautions

• ⚠️ Let the engine cool completely before working around the intake manifold.
• ⚠️ Disconnect the negative battery cable before unplugging the electronic throttle body.
• ⚠️ Keep dirt, tools, and loose hardware out of the exposed intake ports.
• ⚠️ Never start the engine while the intake manifold is removed.
• ⚠️ Do not pull on electrical wires; release each connector lock first.
• ⚠️ Work on one coil connector at a time to avoid mixing connections.

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🔧 Required Tools

You'll need the following tools for this repair:

• 8mm socket
• 10mm socket
• 13mm socket
• 1/4-inch drive ratchet
• 3/8-inch drive ratchet
• 3-inch socket extension
• 6-inch socket extension
• Inch-pound torque wrench rated 40-200 in-lbs
• Foot-pound torque wrench rated 10-75 ft-lbs
• Small flat-blade screwdriver
• Plastic trim removal tool
• Needle-nose pliers
• Clean shop vacuum
• Clean lint-free shop towels
• Masking tape and permanent marker
• Mechanic’s gloves
• Safety glasses

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🔩 Required Parts

HowToo sells all the parts you need for this repair:

• Ignition coils - Qty: 6
• Upper intake manifold gasket set - Qty: 1

Replace all six coils together if they are original or have similar mileage. If replacing only a diagnosed failed coil, install one coil and retain the remaining serviceable units.

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📋 Before You Begin

• 📍 Park your Impala on level ground, shift into Park, apply the parking brake, and switch the ignition off.
• 🌡️ Allow the engine to cool for at least 30 minutes.
• 🔋 Open the hood. Use a 10mm socket to disconnect the negative battery terminal, then position the cable where it cannot touch the terminal.
• 🏷️ Use masking tape and a permanent marker to label unfamiliar hoses and electrical connectors before disconnecting them.
• 🧹 Clean loose dirt from the top of the engine with a shop vacuum before opening the intake system.
• 🔒 Keep the key or keyless transmitter away from the vehicle while connectors are unplugged.

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🔨 Step-by-Step Instructions

Follow these steps in order:

Step 1: Remove the engine appearance cover

• Grip the plastic engine cover at its reinforced edges and pull upward to release its rubber mounting grommets.
• Use a plastic trim removal tool under a stubborn mounting point rather than forcing the cover.
• Set the cover aside where it cannot be stepped on.

Step 2: Remove the air intake duct

• Use a small flat-blade screwdriver to release the electrical connector lock, then unplug the mass airflow sensor without pulling its wires.
• Use an 8mm socket and 1/4-inch drive ratchet to loosen the clamps at the air cleaner and throttle body.
• Use needle-nose pliers to release any spring clamp, then disconnect the breather hose from the duct.
• Lift the intake duct out and cover its open end with a clean lint-free shop towel.

Step 3: Replace the three front ignition coils

• Use a small flat-blade screwdriver to carefully release each coil connector lock, then press the tab and unplug the connector.
• Use a 10mm socket, 3-inch extension, and 1/4-inch drive ratchet to remove each coil retaining bolt.
• Twist each coil gently to release its rubber boot, then pull it straight upward.
• Push each new coil straight down until its boot seats firmly over the spark plug.
• Install the retaining bolts with a 10mm socket and inch-pound torque wrench. Torque to 10 Nm (89 in-lbs).
• Reconnect each electrical connector until its lock clicks.
• Replace one coil at a time.

Step 4: Disconnect the upper intake manifold connections

• Use masking tape and a permanent marker to label the throttle-body, purge-valve, and manifold connections.
• Use a small flat-blade screwdriver to unlock and unplug the electronic throttle-body connector.
• Use a small flat-blade screwdriver to release the purge-valve electrical connector.
• Disconnect the evaporative-emissions line by pressing its release tabs. Do not pry against the plastic fitting.
• Release the positive crankcase ventilation hoses by pressing their locking tabs and pulling on the fittings, not the hoses.
• Use needle-nose pliers to release any remaining hose clamps.
• Disconnect the brake-booster vacuum hose from the manifold fitting.

Step 5: Remove the upper intake manifold

• Use a 10mm socket, 6-inch extension, and 3/8-inch drive ratchet to loosen the manifold bolts gradually.
• Confirm that every hose, wire, and bracket is free before lifting the manifold.
• Lift the upper intake manifold straight upward and place it on a clean work surface.
• Immediately cover every exposed intake port with clean lint-free shop towels.
• Use a shop vacuum around the ports without allowing the nozzle to contact the sealing surfaces.
• Count the port covers before reassembly.

Step 6: Replace the three rear ignition coils

• Use a small flat-blade screwdriver to release each connector lock, then unplug the three rear coil connectors.
• Use a 10mm socket, 3-inch extension, and 1/4-inch drive ratchet to remove the coil retaining bolts.
• Twist each coil gently, then pull it straight out of its spark-plug well.
• Inspect each well for engine oil or water. Do not install a coil into a wet well until the leak is corrected.
• Press each new coil firmly over its spark plug.
• Install the retaining bolts with a 10mm socket and inch-pound torque wrench. Torque to 10 Nm (89 in-lbs).
• Reconnect the electrical connectors until their locks click.

Step 7: Install new intake manifold gaskets

• Use a plastic trim removal tool to lift the old manifold gaskets from their grooves.
• Wipe the manifold and cylinder-head sealing surfaces with clean lint-free shop towels.
• Do not use a metal scraper or allow debris to enter an intake port.
• Press the new upper intake manifold gaskets fully into their grooves.
• Remove all shop towels from the intake ports and count them before installing the manifold.

Step 8: Reinstall the upper intake manifold

• Lower the manifold straight into place without dislodging the new gaskets.
• Start every manifold bolt by hand using a 10mm socket and 6-inch extension.
• Tighten the bolts gradually from the center outward using a 10mm socket and foot-pound torque wrench. Torque to 25 Nm (18 ft-lbs).
• Reconnect the brake-booster hose, crankcase ventilation hoses, evaporative-emissions line, purge-valve connector, and throttle-body connector.
• Pull lightly on each quick-connect fitting to verify that it is locked.

Step 9: Reinstall the air intake duct

• Remove the protective shop towel from the intake duct.
• Fit the duct fully over the throttle body and air cleaner outlet.
• Use an 8mm socket and 1/4-inch drive ratchet to tighten both clamps until secure. Do not crush the plastic duct.
• Use needle-nose pliers to reinstall the breather-hose spring clamp, if equipped.
• Reconnect the mass airflow sensor and engage its connector lock.

Step 10: Reconnect the battery and install the cover

• Use a 10mm socket and 1/4-inch drive ratchet to reconnect the negative battery terminal. Tighten it securely without overtightening.
• Align the engine cover with its mounting points and press straight downward by hand until every grommet seats.
• Remove all tools and loose parts from the engine compartment.

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✅ After Repair

• ✅ Switch the ignition on for 10 seconds without starting the engine, then switch it off for 10 seconds.
• ✅ Start the engine without pressing the accelerator. A slightly uneven idle may occur briefly while the electronic throttle relearns.
• ✅ Listen for a loud hiss and check for disconnected vacuum hoses. A hiss or persistent rough idle can indicate an intake leak.
• ✅ Verify that the malfunction indicator lamp is not flashing. Shut the engine off immediately if it flashes continuously.
• ✅ Let the engine idle for several minutes, then take a short, gentle road test.
• ✅ Recheck the intake duct, electrical connectors, and vacuum-line fittings after the road test.
• ✅ If a diagnostic trouble code remains stored, it may clear after several successful trips or can be cleared with a compatible scan tool.

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💰 DIY vs Shop Cost

Shop Cost: ₹38,000-₹68,000 (parts + labor)

DIY Cost: ₹20,000-₹42,000 (parts only)

You Save: ₹18,000-₹26,000 by doing it yourself!

Local labor rates and imported-parts pricing vary. This repair takes a shop approximately 1.5-2.0 hours.

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