Jump Problem?

Everytime I hold down the spacebar, my character slowly floats up. How do I make it so the holding of the spacebar doesnt make him float upward?

//JUMPING SECTION

if(Input.GetKeyDown (KeyCode.Space) && canJump == true)
{
staminaInfo.staminaBar.fillAmount -= 0.10f;
StartCoroutine(“MyMethod”);

}
if(canJump == false)
{
jumpTimer -= Time.deltaTime;
chMotor.jumping.enabled = false;
}

if(jumpTimer <= 0)
{

canJump = true;
chMotor.jumping.enabled = true;
jumpTimer = 0.7f;

}
if(staminaInfo.staminaBar.fillAmount == 0)
{
canJump = false;
chMotor.jumping.enabled = false;
chMotor.movement.maxForwardSpeed = 6;
chMotor.movement.maxSidewaysSpeed = 6;
}
}
IEnumerator MyMethod() {

yield return new WaitForSeconds(0.1f);

canJump = false;
}

I think you need to change GetKeyDown to GetKey