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2005 Nissan Murano 3.5L DOHC: PO110 and P0420 Codes, Rough Idle, Power Loss and Backfiring After Fix - Diagnosis and Solution

Model: 2005 Nissan Murano 3.5 Dohc Fault Code: P0420 Posted: 2012-06-29 07:42

I have a 2005 Nissan Murano with a 3.5L DOHC engine that came in with diagnostic codes PO110 and P0420, along with a noticeable rough idle. While driving, I observed intermittent power loss and vehicle surging under load. A brief pinging or valve rattle was heard for just a moment when accelerating. Feathering the throttle provided some improvement, but overall performance remained poor. According to the scan tool troubleshooting guide, a common issue on this model is mechanical failure of the timing actuator solenoid. I had not yet replaced this component. During a visual inspection, I noticed oil leaking from the rear cam position sensor. Upon removal, the O-ring was dried out and the housing showed a visible crack. The plug connector was also saturated with oil. I thoroughly cleaned all components and replaced the cam position sensor. After replacement, the engine started immediately, idled smoothly, and initially seemed to be running correctly. However, during a road test after backing out and making a turn, the vehicle died after traveling 20 feet. The sound resembled a backfire through the throttle body. The engine would start again but exhibited surging, bogging, and instability when attempting to accelerate—unable to maintain operation beyond 3–5 seconds. It did not stay running long enough to check for vacuum issues. This led me to suspect that the vehicle may have been operating on the verge of a timing jump, which occurred during the initial drive. My question is: has anyone experienced this same issue? What steps do you recommend for diagnosing and resolving such symptoms? Note: The original codes are PO110 (Cam Position Sensor Circuit Malfunction) and P042 or P0420 (Catalyst Efficiency Below Threshold). I initially believed the issue was solely related to the cam sensor, but later discovered a secondary problem that significantly contributed to the symptoms.

Related fault codes
P0420
Comments (2)
Anonymous 2012-06-29 08:50

PO110 and P0420 are not isolated issues—P0420 suggests catalytic converter inefficiency. A possible root cause could be a faulty pre-cat O2 sensor, which can create backpressure. Try removing the pre-catalyst oxygen sensor to relieve pressure and assess whether symptoms improve. Also, consider that VVT (Variable Valve Timing) issues are common in this engine family. Start with basic checks: oil level and quality. If there's sludge buildup, it may contribute to performance problems. The oil leak from the cam position sensor suggests possible internal contamination or mechanical wear—this could be a sign of sludge accumulation.

Anonymous 2012-06-29 22:00

Yes, only PO110 and P0420 were present. In most cases, an oil level issue would trigger codes like P0011 or P0021 (or P0022), which I’ve already ruled out. I checked the oil level and found it clean—considering 131k miles, there’s no sign of sludge. I actually identified the root cause: the cam position sensor had a cracked housing and worn O-ring, leading to an oil leak. Replacing the sensor resolved both the PO110 code and the oil leak. However, I missed a critical detail—after the backfire incident, I didn’t inspect all engine components. After sitting overnight and revisiting the issue, I discovered that someone prior to ownership had left the air intake duct loose after the MAF sensor. The backfire likely dislodged it further, causing unfiltered air to enter past the MAF sensor. I removed the entire intake system and secured all clamps. After this fix, the vehicle runs smoothly with no surging or stalling. This experience has reinforced the importance of a complete visual inspection—especially after an engine event like backfiring. This may help others facing similar issues. Thanks for the suggestion—I’m now applying the KISS principle: Keep It Simple, Stupid! 😊