RE: Esky LAMA V4 control response.
Check the servos for consistent movement in the right directions. The elevator servo may be intermittent or stripped. Move the cyclic stick in all directions slowly, and quickly, without the rotors turning.
Unplug the heli battery and SLOOOOWWWLY move the servo arms by hand, listening for clicks and feeling for "dead" areas. This would indicate broken gear teeth or a bad servo motor.
Look for binding in the head.
Check all ball links and make sure they're snapped on the ball, not past and onto the thinner "neck" area. This can create tons of slop.