Hello! I'm new here, hopefully somebody will be able to help.
My brother bought a 2019 2.0 Mazda 3 Skyactive, 120hp (gasoline, not diesel). After only a few weeks the car started giving troubles, codes indicated misfire on cylinder 1. We swapped the coils and replaced the spark plugs, no joy.
We replaced the injector on cylinder one, but now the car gives "casual misfirings" basically everywhere and it runs clearly lean. The mechanic tested the in-tank pump and it gives more than 5 bar of pressure, so it's got to be good.
We're now trying to have the other injectors replaced under warranty but there's a big chance the hi-pressure fuel pump is broken... might be the reason that led the former owner to let the car go.
I have the code on the pump but can't find anything with the same exact code... so I'm wondering: would an aftermarket pump for the previous version (up to 2018) work? They look exactly the same but different code.

Denso, pynm 203f0 08C1421053 or sm296100-0522... thanks to everybody willing to chime in!