Nissan Repair: 2000 QX4, bosch platinum, oxygen sensors

Question
QUESTION: I have a 2000 QX4 that I've had trouble with.  It will intermittently throw 0300 and 0325 codes.  Sometimes both at the same time, sometimes not.  Doesn't seem to follow a pattern which throws first (could be 2 separate problems?).  I've replaced plugs, wires, one of the oxygen sensors, distributor cap, andd rotor recently, as well as adjusted the TPS to be in-spec.  The car seems to run fine, but throws the codes.  Sometimes they clear themselves, othertimes I have reset them and they come back anywhere between a couple days to a couple weeks from then.

ANSWER: Jeremy,

The first is a random misfire.  I would make sur ethe plugs were good and that they were not Bosch platinum.  I have had trouble with them throwing this code.  A good double platnum like NGK or Nippondenso should be good.  The second code is the knock sensor.  This is simply a replacement of the knock sensor.

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QUESTION: Plugs are Denso platinum and misfire code was showing before and after replacing.  Gap was checked on all prior to installation.  Any other ideas?  I ordered a knock sensor to see if that will cure that code problem (wasn't sure if it was the sensor or indication of a problem).  Thanks.

Answer
Jeremy,

The random misfire, if the plugs are good and the cap, rotor and wires were replaced lead me to think the distributor is defective.  I would disassemble and look at the optical shutter wheel.  But, be sure to replace the knock sensor is that code did exist first.