Problems throttle response to motors

Hi everyone,

I am trying to built my drone, but I keep encountering the same problem: the motors do not respond well to the throttle of the controller. Any suggestions/help would be appreciated.

I made a small video showing the problem, as shown the motors do not respond simultaneously and when reducing the throttle back to 0 even 1 or 2 motors keep spinning… :

I checked the throttle response from the controller in QGroundcontrol and there the response is fine. I already replaced all the motors once and the power distribution board as well. This did not change anything at all. The only thing I can imagine that might cause the problem is the px4, not sending motor signals correctly to the power distribution board.

Components I m using:
PX4 + PM07 power distribution board + M8N gps module.
4x brushless A2212 1000KV motors and ESC’s (the standard yellow esc’s).
FS-I6X flight controller + FS-IA6B receiver
3S 5000mAH Li-Po.

Hereby several pictures:

Kind regards,

After endless trying I fixed the problem. Seems to be that one of the px4 wires to the PDB got damaged. I replaced the wires and now it works fine.