Code : P0300 may also be accompanied by a 301-312. the number after the 3 indicated the misfiring cylinder
Definition : Random/Multiple Cylinder Misfire Detected
Symptom : Check Engine Light Illuminated and engine misfire, may also detect loss of power or hesitation while accelerating
Cause : The engine will set this code when a misfire is repeatedly detected.
Repair : Replace the failed component on that particular cylinder. Most commonly the Coil Pack
Damage if not repaired : Engine damage to the cylinders rings and damage to the catalytic converter from raw fuel not being burned, not to mention the poor performance and fuel mileage.
When you pull the check engine light codes and p0300 pops up you may ask yourself, What do I do now? See if there is an additional code such as p0302. The number that follows the 3 ( 02 in this case) identify's the problem cylinder. So the problem would be in the number 2 cylinder and in most cases can be cured by replacing the coil pack.
I suggest repairing the problem so in the future if your car has an additional problem it can illuminate the check engine light to let you know you need to fix an issue.