Have you checked for a clogged nozzle?
The brass gear wasn’t aligned? I check the gear and the bearing before I ship them out and the set screws have always been close to the stepper not the heat sink.
You might actually have to turn up the stepper driver for the extruder. Some of them are requiring just about 2 times the power to work right, I can’t figure out why or which ones.
The search doesn’t work for me either, I have no idea how to fix that….