hello to all.
i have a tarrot X4 quad with this config:
motors:T-motor u7
ESC:T-motor T80A
MC: A2 (firmware:latest version)
radio control:futaba 10CG
Battery:2*(5500ma-6cell)
that fly stable and ok and respond to my roll & pitch angle stick command correctly,but in yaw command suddenly become unstable in all axes & cause to crash.

A2 controllers gain :

basic:
roll:130
pitch:130
yaw:120

attitude:
roll:130
pitch:130
vertical:120

please help me               

do you have your IMU and GPS X,Y and Z numbers set correctly?