Ruff idle 'til it dies, w/random misfire on #2-4

My grandson's 2010 VW Passat started stalling with random misfires in cylinders #2 and #4, when he stopped for a traffic light a few days ago. It starts back up immediately, but he had to continue pumping the accelerator to keep it going. The only trouble code that intermittently shows up is the random misfire code. I've already replaced spark plugs, all four ignition coils and visually inspected the coils' electrical connections, but haven't found any issues there. I've also checked for loose and/or broken hoses and vacuum lines and installed a new MAF-sensor. I'm now thinking it might be the Evap Purge valve/solenoid, but I'm also thinking knock-sensor. Does anyone have any experience with this problem and what might be the cause?
All responses are appreciated

BTW, I replaced the intake manifold and runner/flap sensor about 1.5 months ago, at which time I removed the heaviest crude, cleaned and reinstalled the injectors with new o-rings and seals kit. The car has been running fine since then, until a week ago.

If you are sure that ignition is fine then fuel is the next place to look into.

If you are sure that ignition is fine then fuel is the next place to look into.

That is the million dollar question. Have I exhausted all electrical possibilities before I commit to removing the intake one more time, to install all new injectors w/o-rings and seals? I'm going to replace all fuel filters and do a more intense inspection of the coil and injector connectors, just to be thorough. But I'm asking if anyone can think of any other related sensor, valve, etc that might be a cause to this effect, that I have not thought of.

That is the million dollar question. Have I exhausted all electrical possibilities before I commit to removing the intake one more time, to install all new injectors w/o-rings and seals? I'm going to replace all fuel filters and do a more intense inspection of the coil and injector connectors, just to be thorough. But I'm asking if anyone can think of any other related sensor, valve, etc that might be a cause to this effect, that I have not thought of.