Code P306 and P316 both indicate a misfire on cylinder number six. P300 is misfire on unknown cylinder. Car missed and started running very rough. I replaced the coil on plug (COP) and all is fixed. Complete instructions for a Ford Lincoln Mercury V8 found on Crown Victoria, Grand Marquis, Town Car, Mustang, Explorer 4.6L and 5.4L truck. See my OBD2 code scanner review for more info on scanning and erasing codes to clear check engine light (MIL). Codes P0300, P0301, P0302, P0303, P0304, P0305, P0307 or P0308 are similar fixes just different cylinder. Same goes for OBDII codes P0310, P0311, P0312, P0313, P0314, P0315, P0317 and P0318.
