RPMs fluctuating wildly

[Scott2020]

2013 90hp Merc EFI 4 stroke.
Problem began after I changed hi and lo fuel filters, replaced float switch in the FSM, and vac tested the fuel pressure regulator at 5psi for a crack in the hose.
Now between 3k - 4k RPM, rpms will jump around, sometimes every few seconds. At 4k and above, it's nice and steady. I don't see any engine faults on vessel view.
Does it sound like a problem with the fuel pressure regulator? Maybe something wrong with how I put the FSM back together? Did I damage the fuel pressure regulator by vac testing it?

 

[Scott2020]

2013 90hp Merc EFI 4 stroke.
Problem began after I changed hi and lo fuel filters, replaced float switch in the FSM, and vac tested the fuel pressure regulator at 5psi for a crack in the hose.
Now between 3k - 4k RPM, rpms will jump around, sometimes every few seconds. At 4k and above, it's nice and steady. I don't see any engine faults on vessel view.
Does it sound like a problem with the fuel pressure regulator? Maybe something wrong with how I put the FSM back together? Did I damage the fuel pressure regulator by vac testing it?

I rechecked the FSM and I don't see any issues. Now I'm thinking it could be spark related instead of fuel. Perhaps plugs or ignition coil. Would you see the symptoms above if 1 of the 4 cylinder was misfiring? Would I expect to see an engine fault?