Frontier Mixture Preparation Error

My 2011 Nissan Frontier with a gasoline engine is throwing me for a loop. I'm getting a mixture preparation error at 80086 km. Symptoms are reduced engine power, check engine light, rough running, jerking under acceleration, and occasional stalls at idle. I've checked the intake manifold for leaks, cleaned the mass airflow sensor, and even scoped the O2 sensor. Air-fuel ratio seems off, but I can't pinpoint the cause. Any ideas before I start tearing into it?

4 comment(s)

I also own a Frontier, and had similar symptoms. Does the check engine light come on immediately after clearing the error code? Is there any smell of gasoline?

The check engine light comes back on pretty quickly, within a drive cycle or two. As for the smell of gasoline, yes, I do notice it more when the engine is running rough. Any insight based on that?

In my case, I had a defective injection valve, which was causing fuel to flow outside of optimal range. This caused the mixture to become too rich. Considering the gasoline smell, it's likely that you have a similar defect, and I would recommend that you go to a workshop and replace the injector.

Thanks for the pointer! Took it to the shop, and you nailed it – defective injector. New injector installed, and the engine is running smooth as silk. Total repair cost was 515€ Appreciate the help!

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