Jittery stepper

I use the provided example code on my stepper. The motor rotates one or two cycles then the rotation stops and resumes multiple times.

Appreciate your help. here's the code:
```import board
from adafruit_motor import stepper
from adafruit_motorkit import MotorKit

kit = MotorKit(i2c=board.I2C())

kit.stepper1.release()

try:
while True:
print("Double coil steps")
kit.stepper1.onestep(direction=stepper.FORWARD, style=stepper.DOUBLE)
except KeyboardInterrupt:
kit.stepper1.release()