Drivable short-term, but fix now to avoid damage.
P0303 means the engine computer detected a misfire in cylinder number 3. That cylinder isn't burning its fuel mixture correctly, so the engine loses smoothness and power. As a cylinder-specific code, it usually points to a worn spark plug, coil, or injector on cylinder 3.
$80 – $450
Varies by vehicle and root cause.
Only short distances and carefully. A flashing engine light means stop driving and tow the car to prevent catalytic converter damage.
Typically $80-$300 for a plug or coil on cylinder 3 with labor. Injector replacement or compression repairs can cost more, up to $450 or beyond.
It can become serious. A lingering misfire can overheat and destroy the catalytic converter, so addressing it quickly is the smart move.
Yes. An active misfire code and the resulting incomplete combustion will usually cause a failed emissions or smog test until it's repaired.