r/mazdacx3

I have a 2019 Mazda CX-3 that recently threw a P0192 code (fuel rail pressure sensor low input). The car had been running fine, but while driving on the highway it started to stutter a few times, the check engine light came on, and then it began losing power. I had it towed home and scanned it, which is when I got the P0192 code.

One thing I noticed is the oil rises all the way to the top when the car starts for a few seconds, and I mean ALL the way. Which tell me there is pressure going there. (I attached a photo that tries to show this)

I also checked the oil fill opening (where you add engine oil) and noticed that instead of slight vacuum/suction, it’s actually blowing air out, which makes me think there may be excessive crankcase pressure.

I tried replacing the high-pressure fuel pump with a used one from a Mazda 3. The roller was different (smaller), so I swapped my original back onto it. Even with the replacement tho, the oil would rise.

At this point I’m unsure if the problem is the HPFP itself, or something else like bad piston rings? PCV valve looked fine too, just checked today after cleaning the carbon buildup.

Has anyone run into something like this before or have ideas on what to check next? I’m considering buying a brand new HPFP, but it’s expensive so I’d rather narrow it down first! PLEASE HELP THIS CAR HAS 81K MILES.