Parts for your 2018 Lexus Is-Ignition coils

2018 Lexus IS ignition coils — what they do and when to replace them

Yes, the 2018 Lexus IS uses ignition coils. Technical sources including the Lexus Technical Information System (TIS) repair manuals, the Toyota/Lexus Electronic Parts Catalogue, and engine specifications for the 8AR-FTS (2.0-litre turbo), 2GR-FKS/2GR-FSE (3.5-litre V6), and 2AR-FSE (IS 300h hybrid) confirm a coil-on-plug ignition setup across these engines. That means there’s one ignition coil per cylinder, mounted directly on top of each spark plug.

On the 2018 IS, the ignition coil’s job is to step up the battery’s 12 volts into the thousands needed to fire the spark plug precisely when the ECU commands it. Coil-on-plug keeps the spark strong and consistent, reduces energy loss, and helps the IS deliver smooth starts, crisp throttle response, and good fuel economy.

While ignition coils aren’t a scheduled “replace-at-X-kays” service item, they should be inspected whenever spark plugs are replaced (typically around the 100,000 km mark, depending on engine and conditions). Coils can fail earlier if exposed to heat, oil in the plug tubes, or moisture from engine-bay washing.

Common signs a coil is on the way out include a Check Engine light with misfire codes (often P030X), rough idle, hesitation under load, hard starting when cold, and increased fuel use. If a single cylinder is misfiring, swapping coils between cylinders is a handy diagnostic step to see if the misfire follows the coil.

When replacing, quality matters. Genuine or reputable OE-equivalent coils help avoid repeat issues. It’s fine to replace only the faulty unit, though higher-kilometre cars may benefit from doing a matched set, especially if multiple coils test weak. During service, allow the engine to cool, blow away debris before lifting coils, inspect boots for cracking, and apply a small smear of silicone dielectric grease inside the boot to help sealing. Avoid water blasting the engine bay and fix any cam cover oil leaks that can contaminate the plug tubes.

• IS 300 2.0T: four coils (one per cylinder).
• IS 350 and IS 300 AWD V6: six coils.
• IS 300h hybrid: four coils (the petrol engine still uses spark ignition).

Keeping coils healthy is mostly about prevention: clean connectors, dry plug wells, and timely spark plug changes to keep coil loads sensible. If the IS starts to feel a bit off, a quick scan and coil check can save time and fuel.

Popular questions about 2018 Lexus IS ignition coils

How many ignition coils does a 2018 Lexus IS have?
The count depends on the engine. The IS 300 with the 2.0‑litre turbo has four coils, the IS 350 and IS 300 AWD V6 have six, and the IS 300h hybrid has four. Each cylinder gets its own coil-on-plug unit.

Do ignition coils need to be replaced with the spark plugs?
Not by default. Coils aren’t a scheduled replacement item, but they should be inspected when plugs are changed. Replace any coil showing cracking, oil contamination, poor insulation, or that’s linked to a misfire code.

What are the symptoms of a failing coil on a 2018 IS?
Expect rough idle, hesitation, a Check Engine light with P030X misfire codes, sluggish performance, and higher fuel consumption. If a single cylinder is flagged, move the suspect coil to another cylinder—if the fault follows, the coil is likely the culprit.