Originally Posted by bradwilfong
My girlfriend just bought her new used 2000 Xterra 3.3 4wd 5 speed with 120000 miles!
Signed the papers and before she got home the check engine light was on and when sitting at idle starts to flash!
Original codes were p0300 random multiple misfire and p0325 knock sensor.
First I ran some seafoam through the system, took it on a beat ride, then installed factory plugs replacing the 5 bosch platinum 2's and cylinder 6's original plug with no electrode left!
No change at that point.
After doing more research and talking to the Nissan dealer I installed a new factory distributor ordered by vin.
Still no change.
Installed factory wires with no change.
Decided to tackle the knock sensor in hopes it was retarding the timing enough to cause the misfire.
After new knock sensor, upper and lower intake gaskets, and a couple new coolant lines I took care of the knock sensor code!!!!
Random misfire still occurring at idle, comes and goes at times. Decided to try the rest of the can of seafoam with hopes... denied!
Wow, you do bounce around once you get a head of steam up, don't you.
To get a few clarifications...
When you say "No Change", what do you mean?
Do you mean the truck is not running right, or, just that the codes have not reset yet?
You have already tracked down one of the common issues, that pesky #6 plug....the mechanics skip it because its a PITA, each thinking THEY are the first to do so, etc....
If the electrode is MISSING though, that does make one wonder where it is now though....?
My first thought is that its somewhere below where it started, which can certainly lead to trouble.
Another question...at 120K, it was due for a new timing belt and water pump at 105K....was that done?
Was it "Done" by the same consciousness chap who did the spark plugs?
As for the knock sensor...on the non-SC X's, its meaningless, and you could have ignored it. The O2 sensor, sure, makes the rig run crappy when they go south...but, the KS is not needed at all on that year X.
Given the questions on maintenance...a clogged air filter or crack in the intake plenum duct, a fouled MAF sensor, etc...could be present as well.
(And, your diffs and other lubes are probably dry or gunky, and so forth...but that's a separate issue...)
And, I can't help but ask...is there some reason you guys didn't bring it back to the guy who SOLD IT like that?
IE: It SOUNDS like it was "Code Cleared and Sold"...with the codes coming back right after the truck left the lot, etc....?
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2001 Xterra SE, 2003 V6, 5 spd, Shrock Sliders, Bumpers and Skids, Warn 9.5xp Winch w/125' MasterPull II, OBA w/4Gal Tank & 4 CFM Compressor, Revolver Shackles, Deaver 3-Pack + Calmini 2-Pack + OEM Leaves, Bilstein 5150, SLR UCA, Diff Drop, 3" SL, 2" BL, 33x13.5/16 LTB's, Snorkel, Electric Fan Swap, etc...