P0301 on Mazda
Cylinder 1 Misfire Detected
P0301 on Mazda vehicles indicates cylinder 1 misfire detected. Au7o has documented this code across 8 Mazda models — most commonly on 626, CX-3, CX-5. 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 Mazda range from $50 to $5,000, 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 Mazda by Model
Mazda 626(1 issue)
- Distributor Internal Coil and Hall Effect Sensor Failure1993-1997
The 626's distributor assembly contains the ignition coil and hall effect sensor, both of which fail prematurely. The distributor is mounted on the rear of the cylinder head where it is exposed to engine heat. Internal components fail between 80,000-120,000 miles causing intermittent no-start, misfires, and stalling. The failure is often intermittent, making diagnosis difficult.
Mazda CX-3(1 issue)
- Skyactiv 2.0L Intake Valve Carbon Buildup2016-2021
The 2016-2021 Mazda CX-3 with the 2.0L Skyactiv-G direct injection engine develops carbon deposits on the intake valves over time. Because direct injection sprays fuel directly into the combustion chamber rather than over the intake valves, there is no fuel wash to clean the valve backsides. Oil vapors from the PCV (Positive Crankcase Ventilation) system coat the intake valves and bake into hard carbon deposits. This gradually restricts airflow, causing misfires on cold starts, loss of low-end power, and reduced fuel efficiency. Using conventional oils with high volatility worsens the problem by producing more PCV vapors.
Mazda CX-5(1 issue)
- Carbon Buildup on Intake Valves (Skyactiv)2013-2023
Direct-injection Skyactiv engines accumulate carbon deposits on intake valves due to oil vapors from the PCV system. Without port injection to clean valves, carbon can fuse to valve surfaces over time, typically appearing around 65,000+ miles.
Mazda Mazda3(1 issue)
- Carbon Buildup on Direct Injection Intake Valves2012-2025
SkyActiv direct-injection engines lack port injection to wash intake valves, causing carbon deposits to accumulate over time. Carbon buildup restricts airflow, causing rough idle, misfires, and power loss. Typically becomes noticeable around 60,000-80,000 miles.
Mazda Mazda6(1 issue)
- SkyActiv-G Intake Valve Carbon Buildup (Direct Injection)2014-2021
Because the SkyActiv-G direct-injection engine sprays fuel directly into the cylinder, no detergent fuel ever washes the back of the intake valves. Oil vapor drawn through the PCV system bakes onto the hot valve stems and accumulates as hard carbon, typically becoming noticeable on the 2.5L between 60,000 and 100,000 miles. The deposits restrict airflow and cause rough idle and cold-start misfires that are otherwise hard to diagnose.
Mazda MX-5 Miata(1 issue)
- Crankshaft Position Sensor Failure (NB)1999-2005
The NB Miata (1999-2005) crankshaft position sensor (CPS) is a known failure point. The sensor deteriorates from engine heat, causing intermittent stalling, no-start conditions, and random misfires. Failure is often heat-related - the car runs fine when cold but stalls or dies after reaching operating temperature.
Mazda RX-8(1 issue)
- Apex Seal Failure / Compression Loss2004-2012
The Renesis rotary engine in the RX-8 is infamous for apex seal wear and failure, leading to catastrophic compression loss. Apex seals maintain the combustion chamber seal between the rotor and housing. Heat, carbon deposits, and inadequate lubrication cause seals to wear, chip, or break. Compression testing below 6.5 kg/cm2 indicates rebuild is needed. This is the single most common and feared RX-8 issue.
Mazda Tribute(1 issue)
- Ignition Coil Failure and Misfires2001-2011
Ignition coil-on-plug coils fail causing misfires. Ford 3.0L Duratec V6 coils are prone to cracking and arcing. Usually fails one at a time.
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View P0301 across all makes →Frequently Asked Questions
What does P0301 mean on Mazda?▼
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 Mazda specifically, this code is documented across 8 models.
What causes P0301 on Mazda vehicles?▼
Common causes on Mazda: 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 Mazda?▼
Repair costs on Mazda range from $50 to $5,000, depending on the specific model and root cause.
Which Mazda models have P0301 documented?▼
Au7o has documented P0301 on 8 Mazda models: 626, CX-3, CX-5, Mazda3, Mazda6, MX-5 Miata, RX-8, Tribute.