Nissan Repair: 2003 Spec V Sentra-multi-cyl misfire?, car diagnostic, knock sensor

Question
It has 100K km on it and no prior mech. issues. I fired it up yesterday morning and it was running rough, obviously misfiring and the CEL on. I did the in car diagnostic and code "0300" came up. What might be the cause? Need new plugs/wires maybe? Will a diagnostic tool give more info?
Thanks.

Answer
Shane,

The code 0300 is the knock sensor and that can cause all kinds of problems.  A code reader would be nice.  Autozone or Checker will check the codes for free and after you replace the knock sensor they will clear the code.  The plugs are probably in need of replacement and I would recomment NGK or Nippondenso platinum.