spasmodically

/spæzˈmɑdɪkli/
adverb
  1. In a way that happens suddenly, briefly, and irregularly; not steadily or continuously.
    • He only worked on his novel spasmodically, writing a few pages every few months.
    • The lights flickered spasmodically during the storm.
    • The old engine coughed spasmodically before finally starting.