When I start my 03 Rubicon when the engine is cold, it has a knocking sound that goes away once the engine is up to operating temp. I’m not sure where it’s coming from but it doesn’t sound great but goes away when the engine gets up to temp. Its more pronounced when it’s cold outside and I start it, and less so when outside temps are more mild. I attached a video of what it sounds like, sorry for the wind noise and mediocre video quality.