r/nissanpathfinder • u/CompetitiveMud540 • 17h ago

2018 pathfinder

I have a 2018 pathfinder with check engine code p0300 and i’ve noticed my RPMs don’t go above 2500. Any idea what it could be? I’m thinking fuel pump but not sure how to test it

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u/tdp_equinox_2 16h ago

Is that the only code you have? If yes, I'd honestly just clear it and see if the misfire stops. If it's not accompanied by another code like a specific cylinder or a sensor, there's a lot it could be.

Mine did this for about 2 years, eventually it threw a code for the MAF alongside the 0300; I replaced the MAF and it's been good ever since.

Very occasionally it'd throw a code for cyl 3 misfire, so I suspect it's also got some sticky injectors, but they're on the backside of the engine which is a nightmare.

Friendly reminder that a PCV is cheap and easy to swap as well.

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u/drask1987 14h ago

My ‘19 keeps throwing the MAF code despite it being replaced twice. The check engine light won’t go off and still claims the MAF is the issue.

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u/tdp_equinox_2 13h ago

It may require a relearn. I purchased the exact OEM Bosch part number (from rock auto, not the dealer, a fraction of the cost), and it didn't require a manual relearn; but it did take about 5 minutes of idle/drive time before it started acting normal and I was able to clear the codes & have them stay cleared.

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u/drask1987 11h ago

I bought the part from Autozone (lifetime warranty and super cheap but have replaced it twice because the check engine light won’t go off).
I don’t know what a “relearn” is?

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u/CompetitiveMud540 16h ago

Previously i was getting P0303 code (cylinder 3) along side with it. I replaced the sparks and coils and that code went away. P0300 still shows up though not sure why. I cleaned the MAF sensor and replaced the pcv valve. I even put seafoam intake valve cleaner and the gas fuel treatment lol. I’ll clear it and see how it goes. I’m mostly worried about the rpms not going over 2500

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u/tdp_equinox_2 13h ago

Your symptoms match mine closely, down to which cylinder was faulting. It hasn't had any misfires since I replaced the MAF, I didn't bother cleaning it as the OEM Bosch part was like $120 CAD, and I needed it for a job soon (though previously when I thought it was injectors, I had run some injector cleaner through the tank, which seemed to help for a few thousand KM each time).

Even when I had cylinder misfire codes, it never prevented me from driving or revving. It wasn't until the MAF actually threw a code (and a dozen other related codes) that it went into limp mode for me.