Parts for your 2008 Lexus Is-Ignition coils

2008 Lexus IS Ignition Coils: What They Do and How to Look After Them

Technical references confirm ignition coils are absolutely used on the 2008 Lexus IS. The Lexus IS (GSE20/21/25, USE20) Repair Manual details coil-on-plug ignition for the 4GR‑FSE (IS250), 2GR‑FSE (IS350) and 2UR‑GSE (IS F) engines, including inspection steps and fault codes (e.g., P0351–P0358). Toyota’s Electronic Parts Catalogue likewise lists an individual ignition coil assembly for each cylinder across these engines. So yes—ignition coils are relevant and fitted from factory.

On a 2008 Lexus IS, each cylinder gets its own coil-on-plug unit. Those coils transform the 12‑volt supply into a high-voltage spark, lighting off the air–fuel mix exactly when the ECU commands it. That tight control is what gives the IS its smooth idle, crisp throttle response and clean emissions, whether it’s the refined 2.5‑litre IS250, the punchy 3.5‑litre IS350 or the bellowing IS F V8.

There’s no fixed replacement interval for coils, but they do wear with age, heat and vibration. The best time to give them a once‑over is when the spark plugs are serviced (typically around the 100,000–160,000 km mark depending on plugs and driving). Look for cracked housings, swollen or oil‑soaked boots, green corrosion on terminals, or arc tracks. If misfires are logged (P030x) or coil circuit codes pop up (P035x), swap the suspect coil to another cylinder to see if the fault follows—classic coil telltale.

• Common symptoms: rough idle, hard starting, hesitation under load, poor fuel economy, sulphur smell, and a flashing MIL during severe misfire.
• Good practice: use quality OEM‑equivalent coils, keep plug gaps to spec, fix any rocker cover gasket leaks that drip oil into plug tubes, and avoid blasting coils with a pressure washer.

Replacement is straightforward under the bonnet: remove the engine cover, unplug the coil connector, undo the hold‑down bolt, and lift the coil out. Refit is the reverse—lightly seat the boot on the plug, click the connector home, and torque the bolt to the factory spec. On higher‑kilometre cars, it’s smart to replace coil boots when doing plugs. If one coil fails on a V6/V8, many owners replace just the dud, others pre‑emptively service coils on the same bank to cut future labour. Either way, addressing misfires quickly protects the catalytic converters and keeps the Lexus driving as it should.

• How many ignition coils does a 2008 Lexus IS have?
  IS250 and IS350 each use six coil‑on‑plug units—one per cylinder. The IS F uses eight coils for its V8. Being individual coils makes diagnosis and replacement easier because faults can be isolated to a single cylinder.
• How often should the coils be replaced?
  There’s no set schedule. Coils are replaced when they show symptoms or fail tests. Inspect them whenever spark plugs are changed, and consider new boots at that time. Many coils last well beyond 150,000 km if heat and oil intrusion are kept in check.
• Is it safe to keep driving with a bad coil?
  Not recommended. A misfiring cylinder can overheat and damage the catalytic converter, and drivability and fuel use will suffer. If the MIL is flashing or the engine feels rough, it’s best to sort the coil promptly.