P0306 on Lexus: How to Diagnose & Fix
Cylinder 6 Misfire Detected
1 Lexus model · 1 documented issue · $250-$900 repair
P0306 on Lexus by model: symptoms, diagnosis and fix
Aging valve cover gaskets on the 2JZ-GE commonly harden and leak, allowing oil to seep onto the cylinder head, spark plug tube seals, and exhaust side of the engine. Owners often notice a burnt-oil smell, visible oil around the valve covers, and occasional misfires if oil contaminates ignition components. This is one of the most common age-related engine leaks on the first-gen IS300.
Common Symptoms
- burning oil smell
- oil on valve cover edges
- oil in spark plug wells
- light smoke from engine bay
- misfire under load
- oil spots on driveway
How to Fix
Confirm the leak source by cleaning the engine and inspecting around the valve cover perimeter and spark plug wells. Replace both valve cover gaskets, spark plug tube seals, and related grommets; many owners also replace the PCV valve at the same time to reduce crankcase pressure. If misfires are present, inspect and replace oil-soaked coil boots or plugs.
What you need to fix it
Only diagnosis- and fitment-reviewed repair parts are linked here.
- 11213-46030 genuine Lexus intake-side valve-cover gasketOEM11213-46030
Supply the intake-side member of the confirmed 2JZ-GE valve-cover reseal Fitment/availability: Live Add to Cart page identifies the intake side, direct-replacement 11213-46030 gasket and includes 2001-2005 IS300 2JZ-GE fitment. Pair with…
- 11214-46011 genuine Lexus exhaust-side valve-cover gasketOEM11214-46011 (replaces 11214-46010)
Supply the exhaust-side member of the confirmed 2JZ-GE valve-cover reseal Fitment/availability: Live Add to Cart page identifies the exhaust side, direct-replacement 11214-46011 gasket, superseding 11214-46010, and includes 2001-2005 IS3…
- 12204-46031 genuine Lexus PCV valveOEM12204-46031
Inspect its grommet and hoses and confirm VIN before ordering.
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Owner tips & cautions
- TipA PCV valve replacement is cheap preventive maintenance when doing this job.
Sources for this issue (1)
P0306 code reference
General diagnostic-code context. The code alone does not confirm a cause for your vehicle; use the applicable issue card and its sources.
Frequently asked questions
What does P0306 mean on a Lexus?
P0306 stands for "Cylinder 6 Misfire Detected." This code means the engine computer detected a misfire on cylinder 6 — that cylinder isn't burning its fuel-air mixture properly. The computer senses misfires by watching for tiny variations in crankshaft speed each time a cylinder should fire, and when cylinder 6 repeatedly fails to contribute, this code sets. You may feel a shake or stumble, especially at idle or under load, along with reduced power and possibly a flashing check-engine light, which signals a misfire severe enough to damage the catalytic converter. A misfire comes down to a problem with spark, fuel, or compression in that cylinder. On Lexus it is documented across 1 model: IS.
What are the most common causes of P0306?
The most common causes of P0306 are: Worn or fouled spark plug on cylinder 6, Failed ignition coil for cylinder 6, Clogged, leaking, or failed fuel injector, Vacuum or intake air leak affecting that cylinder, Low compression (worn rings, burnt valve, head gasket), Damaged plug wire or coil connector, Carbon buildup or worn valvetrain components. The specific cause varies by vehicle.
How much does it cost to fix P0306 on a Lexus?
Published repair estimates on Lexus range from $250 to $900 depending on the model and root cause. If an issue mentions a recall or campaign, check your VIN with the manufacturer or NHTSA and confirm eligibility and coverage with a dealer.
Looking for P0306 on a different make?
View P0306 across all makes →Content compiled with AI assistance using NHTSA complaints, TSBs, and owner reports. May contain errors. Always verify with your vehicle's service manual.