Toyota Check Engine Code
P0300 on Toyota
Random / Multiple Cylinder Misfire Detected
Also covers: Lexus, Scion
P0300 on Toyota: what makes it different
P0300 — a random/multiple cylinder misfire — appears across a wide range of Toyota models and engine families. Toyota's inline-4 and V6 engines are generally reliable but have documented misfire triggers tied to specific design traits, including carbon buildup on direct-injection variants, distributor-era ignition failures, and coil-on-plug failures on the 2GR-FE V6. The code is especially common on high-mileage Camrys, Corollas, Tacomas, and 4Runners.
Most-affected engines
- 1ZZ-FE 1.8L (Corolla, Matrix, Celica)
- 2AZ-FE 2.4L (Camry, RAV4, Tacoma)
- 2GR-FE 3.5L V6 (Camry, RAV4, Highlander, Sienna, 4Runner)
- 5VZ-FE 3.4L V6 (4Runner, Tacoma, Tundra — distributor ignition)
- 2TR-FE 2.7L (Tacoma, 4Runner, FJ Cruiser)
Common model years: 1998–2022
Most likely cause on Toyota
Failed or weak ignition coil (coil-on-plug) causing intermittent or consistent misfires across multiple cylinders, most prevalent on the 2GR-FE V6 platform.
Known Toyota engine-family issues
The 2AZ-FE 2.4L engine found in Camrys and RAV4s from the mid-2000s has a well-documented oil consumption problem, where worn piston rings allow oil to enter the combustion chamber, fouling spark plugs and causing misfires. Toyota extended warranty coverage on this engine for this specific issue. The 2GR-FE 3.5L V6 is known for coil failures on the rear cylinder bank because heat soak from the firewall accelerates coil degradation; replacing only one coil often leads to repeat visits as neighboring coils fail shortly after. It is generally recommended to replace all six coils and all six plugs at once on this engine.
Toyota-specific causes (most common first)
- Failed coil-on-plug unit on the 2GR-FE V6, which is known for coil degradation particularly on the rear bank where heat is trapped
- Carbon buildup on intake valves of the 2GR-FE and other port-injected high-mileage engines restricting mixture formation
- Worn or cracked spark plug causing misfires that jump cylinders as the fault worsens
- Oil fouling of spark plugs due to the well-documented oil consumption issue on the 2AZ-FE 2.4L engine
- Cracked distributor cap or worn distributor rotor on older 5VZ-FE 3.4L V6 trucks and 4Runners
- Lean condition from a dirty or failing mass airflow sensor causing a random misfire pattern
Toyota-specific diagnostic tip
On any Toyota with a P0300, start by pulling all spark plugs and inspecting them. On a 2AZ-FE, look for oil-fouled plugs indicating the consumption issue. On a 2GR-FE, rotate the rear-bank coils to the front bank and clear codes — if the misfire follows the coil to a new cylinder, you've confirmed a bad coil without buying parts first. On older distributor-equipped Toyotas like the 5VZ-FE, remove the distributor cap and inspect the rotor tip and cap contacts for carbon tracking or corrosion.
Symptoms drivers report
- Check engine light (often flashing — flashing means catalytic damage is happening now)
- Rough idle, shuddering
- Loss of power
- Hesitation or stumble under load
- Smell of unburned fuel
Typical repair cost on Toyota
Most Toyota owners fix P0300 for between $80 and $600, depending on which underlying cause turns out to be at fault. Start with the most-likely cause for your vehicle — Failed or weak ignition coil (coil-on-plug) causing intermittent or consistent misfires across multiple cylinders, most prevalent on the 2GR-FE V6 platform. — before throwing parts at it.
Toyota P0300 FAQ
My Toyota Camry has P0300 plus P0302 and P0304 — what does that mean?
Multiple specific cylinder codes alongside P0300 suggest either a shared component failure (like a bad fuel injector driver or vacuum leak causing a lean condition across cylinders) or coincidentally failed coils on those cylinders. On the 2AZ-FE, oil fouling of plugs in multiple cylinders at once is also common. Check spark plugs for oil contamination first.
How often should I replace spark plugs on my Toyota to prevent misfires?
Toyota iridium spark plugs are rated for 60,000–120,000 miles depending on the engine, but real-world experience on the 2GR-FE suggests replacing them at 60,000–80,000 miles along with the ignition coils to avoid misfire issues, especially on the rear cylinder bank.
Is P0300 on my Toyota an emergency?
A steady P0300 at idle or under light load is not immediately dangerous, but a severe or flashing check engine light during acceleration indicates an active misfire that can rapidly damage the catalytic converter. If the light flashes, reduce load and speed and have it diagnosed promptly.
Related codes
Drive a different make? See the general P0300 guide for cross-vehicle causes and symptoms.
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Most common fix for P0300:
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