2014–2020 Lexus IS
By Tom Becker ✓ Certified Mechanic · Published Sep 21, 2026 · Updated Oct 22, 2026
Save $80 by doing it yourself! Shop cost: $400
Quick answer: Spark Plug Replacement on a 2014–2020 Lexus IS is rated Moderate and takes about 2-3 hours. You'll need 9 tools for this job, and parts cost about $320. This guide walks you through the full job step by step, including the mistakes to avoid.
| Part Name | Part Number | Price | Buy |
|---|---|---|---|
| Iridium Spark Plugs | — | $120.00 | |
| Ignition Coil Set | TRQ ICA71771 | $200.00 |
About prices: shown prices are typical retail averages and change frequently; cheaper alternatives may be available. Confirm the current price before buying.
💡 Pro tip: Order all parts at once to save on shipping
Follow these steps carefully
Work only on a cold engine. Hot aluminum heads can pull threads when plugs are removed. Disconnect the negative battery terminal if required by your procedure.
I only do plugs on a stone-cold engine — hot aluminum heads can pull the threads right out with the plug, and a thread repair is a whole different afternoon.
Remove any engine cover or intake tube blocking the coils. Label coil connectors or photograph their positions before unplugging.
Unplug the coil connector, remove the coil hold-down bolt, and pull the coil straight up. Work one cylinder at a time to avoid mixing parts.
Blow loose dirt from the well. Use a spark-plug socket with a rubber insert and extension to remove the plug. Inspect the tip for oil, coolant, or abnormal wear.
Confirm the new plug part number and set the gap to the manufacturer specification if required (many iridium plugs are pre-gapped). Start the plug by hand to avoid cross-threading.
Torque the plug to the spec in the service information (typically a modest ft-lb or degree turn after seating). Do not overtighten \u2014 stripped head threads are expensive.
I use a torque wrench on these — 'snug' is how threads get stripped, and a stripped plug hole in an aluminum head turns a tune-up into a machine-shop bill.
Press the coil fully onto the plug, reinstall the hold-down bolt to snug\/spec, and reconnect the electrical connector until it clicks.
Refit covers\/intake components, reconnect the battery if removed, and start the engine. Listen for misfires and confirm a smooth idle. Clear any residual codes if a light remains.
Test your repair before closing everything up. If something doesn't work right, double-check your steps.
⚠️ Common Mistakes to Avoid
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