New here, have a used Phantom 2 vision + that needed some work to it, ie 2 new motors and esc boards, after work was done and all soldered good, it now takes off and seems to twitch in GPS or hovering, 1 motor also seems to be somewhat "tighter" then the other 3 as it stops spinning sooner then the others when shutting down, any thoughts on what to check on this and thanks.