Posted: Jan 09 2009 at 3:55pm | IP Logged

I have a 2002 Nissan Frontier SE (V6 VG33) with 119k.  I am the original owner and it has been a super reliable vehicle.   My "service engine soon" light has been constantly illuminated for nearly a month.  I went to my local Advanced Auto Parts to purchase a OBDII scanner to see what was activating the light.  They guy there said he could use theirs to see what the problem was, so I said sure.  It had 6 error codes total, but all codes were from the Oxygen Sensor and the Knock Sensor.  I did not write down the code numbers, but I know the Knock Sensor code was something to do with being on the "high" end.

The AAP employee said the knock sensor was easy to replace, and that he would replace that first and my oxygen sensor error codes might go away.  After researching online and referring to my Haynes manual, I learned that the Intake Manifold had to be removed to get to the Knock Sensor, so it isn't an easy thing to replace.  I also read that Oxygen sensor problems can throw a Knock sensor error code.

Anybody dealt with this problem?  I don't want to spend the money and time replacing my knock sensor only to find out that the problem is really something else.  I'm just looking for a little direction from somebody that has experience with this.  The truck runs well.  I have noticed in the past two weeks a few times when it was idling in drive that it seemed to vibrate really bad, almost stalling... however it does not do that consistantly.

Spark plugs, distributor, belts & hoses were all replaced at 96k.  I use Chevrons fuel additive every 5k.  The truck is definately well taken care of.

Posted: Mar 18 2009 at 7:17pm | IP Logged

I have the 2.4 4 cylinder.  It has *two* o2 sensors.  Make sure you get both of them.  One is right on the engine, and the other is down near the catalytic converter.  Cheap to replace.

I replaced mine at around 100,000, even though no codes were present.  My gas mileage went up about 5% with new sensors and a tuneup.