Fault Codes/Generac/P0300GeneracP0300WarningSensorsWhat This Code MeansNo activity detected from the O2 sensor circuit.; Engine misfiring; Rough idlePossible Causes•Faulty O2 sensor•Faulty spark plug•Vacuum leakSuggested Actions1Test the O2 sensor.2Replace the O2 sensor if faulty.3Replace spark plugs4Inspect and repair vacuum linesRelated Generac Fault CodesSHUTDOWN SWITCH0032010031190031180024936-66-56-46-36-24-44-3Browse all Generac fault codes→ASK RUDY ABOUT THIS FAULTGet a diagnosis walkthrough for P0300 on your specific Generac unit — cited to the OEM manual, not a forum guess.TRY IT FREE