Home › Forums › Stay Dirty Lounge › Service and Repair Questions Answered Here › 1998 Honda Civic p1399 p0300 › Reply To: 1998 Honda Civic p1399 p0300 March 11, 2021 at 1:34 pm #989383 Richard KirshyParticipant Assuming you did these things after the code showed up. Might check for a blocked passage in the EGR system