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P0302 and P0325 Fault Diagnosis: 1997 Nissan Pathfinder V6 with Warm-Start Misfire

Model: 1997 Nissan Pathfinder Fault Code: P0302 Posted: 2007-07-13 11:22

Vehicle: 1997 Nissan Pathfinder (4WD, 3.3L V6, automatic transmission, A/C), 162,000 miles Diagnostic Codes: P0302 (cylinder #2 misfire) and P0325 (knock sensor fault) Issue Description: After the engine reaches normal operating temperature, a brief misfire occurs on cylinder #2 during warm restarts—lasting 20 to 120 seconds—and resolves afterward. The vehicle starts smoothly on cold starts. Component Inspection: - Spark plugs, plug wires, distributor cap, and rotor have been inspected and found to be in good condition. - No visible coolant leaks are present. Hypothesis: My initial assumption is that the fuel injector for cylinder #2 may be faulty, potentially causing a misfire that triggers the knock sensor (P0325). Is this a plausible explanation? Access Concerns: The #2 fuel injector is located beneath the upper intake manifold and is the first injector on that side. I am wondering whether it's possible to replace this injector without removing the entire upper intake manifold—perhaps by simply removing the distributor cap or the distributor itself for better access. Request: Any guidance on diagnosing the root cause (misfire vs. knock sensor trigger) and practical steps for replacing the injector would be greatly appreciated. Ray Fowler

Related fault codes
P0302P0325
Comments (11)
Anonymous 2007-07-13 11:47

This post belongs in the P0XXX diagnostic forum—moved accordingly.

Anonymous 2007-07-13 11:53

A fuel injector leak could cause intermittent misfires, especially during warm starts. I recommend performing a fuel pressure leak-down test to confirm whether the #2 injector is leaking.

Anonymous 2007-07-13 11:55

The term 'fussy dice' appears to be a typo—intended meaning was likely 'fuzzy dice'. The vehicle has fuzzy dice mounted on the rearview mirror, which is a minor detail but may have been confusing for readers. Clarified in the original post.

Anonymous 2007-07-13 12:41

The misfire occurs only during warm starts and resolves after a short period—this suggests a transient fuel delivery issue rather than a permanent component failure. A diagnostic test with ignition and fuel pressure monitoring while the problem occurs is recommended to pinpoint the source.

Anonymous 2007-07-13 13:25

The engine does not show signs of oil consumption or blue smoke during operation, and no valve guide leaks are indicated by cold-start behavior. This reduces the likelihood of internal combustion issues such as worn valve seals.

Anonymous 2007-07-13 13:29

A fuel pressure leak-down test is a valuable diagnostic step to evaluate injector integrity. If the issue persists, consider whether a vacuum leak or vapor lock could be contributing—especially in older vehicles with aging hoses and connectors.

Anonymous 2007-07-13 13:33

I plan to perform a fuel pressure leak-down test as suggested. Would a bottle of injector cleaner (e.g., Lucas brand) help resolve the issue? While I’m skeptical about additives, it’s worth trying in some cases. Additionally, is it feasible to replace the #2 injector without removing the upper intake manifold? Any insight on access would be helpful.

Anonymous 2007-07-13 13:45

Injector cleaner may provide temporary relief if the issue stems from minor clogs—but it won’t fix a faulty or leaking injector. The root cause must be addressed through proper diagnostics before relying on additives. Regarding access: I’m unsure whether the #2 injector can be replaced without removing the upper intake manifold, as its physical design and mounting are not fully documented in available service manuals.

Anonymous 2007-07-13 14:25

The length of the injector and clearance around it will determine if removal is possible. If the two mounting screws can be loosened without dropping one, there may still be enough space to extract the injector manually. No oil consumption or blue smoke observed during operation suggests that valve guides or seals are not severely worn.

Anonymous 2007-07-13 14:46

It's worth attempting to remove the #2 fuel injector. If it proves too long or difficult to extract, removing the upper intake manifold at that time may be necessary for a proper replacement.

Anonymous 2011-06-09 17:42

A common cause of P0302 and P0325 in 1996–1998 Nissan Pathfinders is a corroded metal vacuum hose located above the rear driver’s side tire. This hose connects from the charcoal canister to the purge valve via a metal section that deteriorates over time, leading to intermittent vacuum loss. This leak affects cylinder #2 during warm starts, causing a brief misfire before resolving. Mechanics familiar with this issue should be aware of it—look for visible corrosion in the metal hose segment connecting the canister and purge valve.