What does the P0300 code mean?

P0300 stands for Random/Multiple Cylinder Misfire Detected. The engine computer monitors crankshaft speed and has seen misfires on two or more cylinders, but no single cylinder is failing badly enough to earn its own code. It points to a fault affecting the whole engine, such as ignition, fuel supply, or a vacuum leak, rather than one bad cylinder.

What causes a P0300 code?

The usual culprits, in rough order, are worn spark plugs, failing ignition coils, a vacuum leak at the intake, weak fuel delivery from a tired pump or clogged injectors, carbon buildup or a stuck-open EGR valve, and, less often, low compression from a head gasket or worn rings. Because several cylinders are affected, look for one shared cause rather than four separate faults.

Is it safe to drive with a P0300 code?

It is not recommended. With a steady light you can usually drive a short distance to a garage gently, but with a flashing light you should stop as soon as it is safe. Active misfires push unburned fuel into the exhaust, which can overheat and ruin the catalytic converter within minutes, turning a plug job into a far larger repair.

How do you fix and clear a P0300 code?

Fix the underlying cause first, most often a fresh set of spark plugs and any failed ignition coil, then a vacuum leak or fuel issue if those are not it. Once the repair is done, the code can be cleared with a scan tool, or many cars clear it themselves after several drive cycles with no new misfires. Clearing the code without fixing the fault only makes it return.

How much does it cost to fix a P0300?

It depends entirely on the cause. A full set of spark plugs is around 60 to 230 EUR fitted, and a single ignition coil runs about 40 to 200 EUR. A vacuum leak is often cheap parts but labour-heavy, and a fuel injector or compression-related repair can run several hundred euros. Diagnosing it correctly first is what keeps the bill down.

P0300: Random/Multiple Cylinder Misfire Detected

Quick Answer

Not safe to drive

P0300 means the engine computer has detected misfires across several cylinders without being able to pin them to one specific cylinder, so it flags the whole engine rather than a single cylinder. The most common trigger is worn or fouled spark plugs that no longer spark reliably, and a full set costs about 60 to 230 EUR fitted. A steady light is a warning, but a flashing light means raw fuel is reaching the catalytic converter, so stop driving.

Severity: High · Misfire
Estimated repair cost: From €60 to €700+, varies by vehicle

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What does P0300 mean?

P0300 is a misfire-related diagnostic trouble code classified as high severity. When your vehicle's ECU detects this condition, it stores P0300 and illuminates the check engine light.

What are the symptoms of P0300?

If your vehicle has triggered P0300, you may notice one or more of these symptoms:

Check engine light flashing during the misfire or staying steadily on
Rough idle, shaking, or noticeable engine vibration at a stop
Hesitation or stumbling when you press the accelerator
Loss of power, especially under load or going uphill
Increased fuel consumption and harder cold starts
Strong raw fuel smell from the exhaust

What causes P0300?

Here are the most common causes of P0300:

Worn or fouled spark plugs, which can no longer produce a strong enough spark to ignite the mixture in several cylinders
: high
Failing ignition coils or coil packs, which deliver a weak or intermittent spark and often cause misfires that move between cylinders
: high
Vacuum leak at the intake manifold gasket or a cracked hose, which leans out the mixture across all cylinders and upsets combustion
: medium
Fuel delivery shortfall from a weak fuel pump or clogged injectors, which starves multiple cylinders of fuel under load
: medium
Carbon buildup on intake valves or an EGR valve stuck open, which dilutes the intake charge and disrupts ignition on direct-injection engines
: medium
Low compression from a head gasket leak or worn piston rings, which leaves some cylinders unable to fully burn the charge
: low

Is it safe to drive with P0300?

No - address this immediately. Driving with active misfires can damage the catalytic converter within minutes and may cause loss of power at dangerous moments. Pull over safely and address immediately.

How do you diagnose P0300?

Follow these steps to pinpoint the root cause of P0300:

Scan for companion codes (P0301 to P0312). If a cylinder-specific code is also stored, start with that cylinder before treating P0300 as a whole-engine fault
Inspect the spark plugs for wear, oil or carbon fouling, and a worn electrode gap. Replace the full set if they are past the maker's service interval or if several look fouled
Test the ignition coils, swapping one coil to a different cylinder to see if the misfire follows it, or measuring resistance with a multimeter against spec
Smoke-test the intake for vacuum leaks, or spray carb cleaner around the intake manifold gasket and hoses and listen for an idle change
Check fuel pressure with a gauge. It should hold steady at the maker's spec, typically around 2.8-4.1 bar (40-60 psi) on port-injection engines, and not drop under load
Inspect the EGR valve for sticking and check intake valves for carbon on direct-injection engines, then run a compression or leak-down test if everything else checks out

How much does P0300 cost to fix?

Repair costs for P0300 vary depending on the root cause and your vehicle. Here are typical estimates:

Repair	Parts Cost	Labor Cost	Total Estimate	DIY Difficulty
Replace spark plugs (full set)	€20–€80	€40–€150	€60–€230	Easy
Replace ignition coil(s)	€30–€200	€40–€120	€70–€320	Moderate
Fix vacuum leak	€10–€80	€60–€200	€70–€280	Moderate
Replace fuel injectors	€100–€400	€100–€300	€200–€700	Professional

Prices estimated as of March 2026. Costs vary by region, vehicle, and shop.

Full repair guides

Engines known for this code

P0300 on specific vehicles

P0300 behaves differently depending on your vehicle. Select your car below for model-specific causes and known issues:

P0300 on Hyundai

Hyundai Santa Fe

See Hyundai-specific causes & cost

P0300 on Kia

Kia Sorento

See Kia-specific causes & cost

P0300 on Nissan

Nissan Juke

See Nissan-specific causes & cost

P0300 on BMW

BMW 3 Series

See BMW-specific causes & cost

P0300 on Volkswagen

Volkswagen Golf

See Volkswagen-specific causes & cost

P0300 on Audi

Audi A4

See Audi-specific causes & cost

P0300 on Ford

Ford Focus

See Ford-specific causes & cost

P0300 on Toyota

Toyota Camry

See Toyota-specific causes & cost

P0300 on Honda

Honda Civic

See Honda-specific causes & cost

These codes are often seen alongside P0300 or indicate related issues:

Common questions about P0300

What does the P0300 code mean?: P0300 stands for Random/Multiple Cylinder Misfire Detected. The engine computer monitors crankshaft speed and has seen misfires on two or more cylinders, but no single cylinder is failing badly enough to earn its own code. It points to a fault affecting the whole engine, such as ignition, fuel supply, or a vacuum leak, rather than one bad cylinder.
What are the symptoms of P0300?: The most common signs are a rough or shaking idle, hesitation when you accelerate, a loss of power under load, harder cold starts, and worse fuel economy. The check engine light may glow steadily or flash. A flashing light during the misfire is the serious case, it means raw fuel is reaching the catalytic converter.
What causes a P0300 code?: The usual culprits, in rough order, are worn spark plugs, failing ignition coils, a vacuum leak at the intake, weak fuel delivery from a tired pump or clogged injectors, carbon buildup or a stuck-open EGR valve, and, less often, low compression from a head gasket or worn rings. Because several cylinders are affected, look for one shared cause rather than four separate faults.
Is it safe to drive with a P0300 code?: It is not recommended. With a steady light you can usually drive a short distance to a garage gently, but with a flashing light you should stop as soon as it is safe. Active misfires push unburned fuel into the exhaust, which can overheat and ruin the catalytic converter within minutes, turning a plug job into a far larger repair.
How do you fix and clear a P0300 code?: Fix the underlying cause first, most often a fresh set of spark plugs and any failed ignition coil, then a vacuum leak or fuel issue if those are not it. Once the repair is done, the code can be cleared with a scan tool, or many cars clear it themselves after several drive cycles with no new misfires. Clearing the code without fixing the fault only makes it return.
How much does it cost to fix a P0300?: It depends entirely on the cause. A full set of spark plugs is around 60 to 230 EUR fitted, and a single ignition coil runs about 40 to 200 EUR. A vacuum leak is often cheap parts but labour-heavy, and a fuel injector or compression-related repair can run several hundred euros. Diagnosing it correctly first is what keeps the bill down.

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