erratic
US /ɪˈræt̬.ɪk/
UK /ɪˈræt̬.ɪk/

1.
errático, irregular, imprevisível
not regular or consistent in movement, behavior, or quality
:
•
His breathing was shallow and erratic.
Sua respiração era superficial e errática.
•
The car's engine was making erratic noises.
O motor do carro estava fazendo ruídos erráticos.