P0301 on Porsche
Cylinder 1 Misfire Detected
P0301 on Porsche vehicles indicates cylinder 1 misfire detected. Au7o has documented this code across 4 Porsche models — most commonly on 718 Cayman, 911, Boxster. P0301 means the engine computer detected a misfire specifically in cylinder 1 — the spark didn't ignite the fuel properly, or the fuel/air mix didn't burn as it should. The computer detects this by sensing tiny variations in crankshaft speed each time a cylinder fires. A misfire wastes fuel, raises emissions, and can damage the catalytic converter if it's severe or persistent (a flashing check engine light usually warns of active, converter-damaging misfires). Because the code points to one specific cylinder, the cause is usually an ignition, fuel, or compression problem isolated to that cylinder. Typical repair costs on Porsche range from $700 to $25,000, depending on the specific model and root cause.
Common Causes of P0301
- •Worn or fouled spark plug in cylinder 1
- •Failed ignition coil or coil pack for cylinder 1
- •Faulty or clogged fuel injector for cylinder 1
- •Vacuum or intake air leak affecting that cylinder
- •Bad spark plug wire (on applicable engines)
- •Low compression (worn rings, leaking or burnt valve, head gasket)
- •Carbon buildup on intake valves
- •Wiring or connector fault to the coil or injector
P0301 on Porsche by Model
Porsche 718 Cayman(1 issue)
- Direct Injection Intake Valve Carbon Buildup2017-2025
The 718 Cayman turbo flat-four and naturally aspirated flat-six engines use direct injection, which does not wash the intake valves with fuel. Carbon deposits accumulate on the intake valves over time, restricting airflow and causing rough idle, misfires, and power loss. The turbo engines are more prone due to higher intake temperatures.
Porsche 911(2 issues)
- Cylinder Bore Scoring (Nikasil Wear)2009-2019
The 991-generation 911 suffers from cylinder bore scoring where the Lokasil cylinder liners develop deep vertical scores, typically on cylinders 1 and 6. This is caused by inadequate oil supply to the cylinder walls during cold starts and short-trip driving. The issue results in excessive oil consumption and eventually requires engine rebuild or replacement.
- Direct Injection Intake Valve Carbon Buildup2009-2019
The direct injection system on 991 engines does not spray fuel over the intake valves, allowing carbon deposits to accumulate on the valve stems and ports. Over time this restricts airflow, causing rough idle, misfires, and reduced power. The flat-six layout makes walnut blasting more labor-intensive than on inline engines.
Porsche Boxster(1 issue)
- Cylinder Bore Scoring2005-2012
The M96 and M97 engines in the Boxster develop cylinder bore scoring similar to the 911. Scoring typically occurs on cylinders 1 and 6 due to uneven oil distribution in the flat-six layout. Symptoms begin with increased oil consumption and progress to misfires and rough running.
Porsche Cayman(1 issue)
- Cylinder Bore Scoring2006-2016
The Cayman M97 and MA1 flat-six engines develop bore scoring on cylinders 1 and 6, identical to the pattern seen in the 911 and Boxster. The Cayman GT4 with its 3.8L 911-derived engine is also affected. Oil starvation at the cylinder walls during cold starts is the primary cause.
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View P0301 across all makes →Frequently Asked Questions
What does P0301 mean on Porsche?▼
P0301 stands for "Cylinder 1 Misfire Detected." P0301 means the engine computer detected a misfire specifically in cylinder 1 — the spark didn't ignite the fuel properly, or the fuel/air mix didn't burn as it should. The computer detects this by sensing tiny variations in crankshaft speed each time a cylinder fires. A misfire wastes fuel, raises emissions, and can damage the catalytic converter if it's severe or persistent (a flashing check engine light usually warns of active, converter-damaging misfires). Because the code points to one specific cylinder, the cause is usually an ignition, fuel, or compression problem isolated to that cylinder. On Porsche specifically, this code is documented across 4 models.
What causes P0301 on Porsche vehicles?▼
Common causes on Porsche: Worn or fouled spark plug in cylinder 1, Failed ignition coil or coil pack for cylinder 1, Faulty or clogged fuel injector for cylinder 1, Vacuum or intake air leak affecting that cylinder, Bad spark plug wire (on applicable engines). Specific causes vary by model and year — see the per-model sections below.
How much does it cost to fix P0301 on a Porsche?▼
Repair costs on Porsche range from $700 to $25,000, depending on the specific model and root cause.
Which Porsche models have P0301 documented?▼
Au7o has documented P0301 on 4 Porsche models: 718 Cayman, 911, Boxster, Cayman.