Tbh i doubt you have a sticky plunger,the fuel pressure is normal enough to force them down and obviously the plate being pulled in by the turbo forces it back up.This operation done a few times normally unsticks a dry metering unit(recently changed or not ran for a while). If it ran a little then cut out it sounds more like your running a wee bit too lean to me. Maybe it just need a damn good setup just to refresh the co2 setting. You could try turn the mixture adjustment 1/4 or 1/2 a turn clockwise to give it a little more fuel. If that doesnt do it turn it back to where it was.
Check all the pipes in the boost circuit as an air leak may give a similiar fault.
I would change the fuel filter at this point just as a precaution,get a clean bowl and empty the contents of the old filter in and check for debree.