Hey mate, ive just purchased an 04 ba falcon about a fortnight ago. Ive had this exact problem. Took it to a relative mechanic, he has cleaned my throttle body(fixed the rough idle and he has cleaned the actuators and has found that one of the cam shaft sensors were nakered. He just replaced it today, car goes like a dream. He's had it booked in for cylinder balance to assess any further issues but is confident that the cam shaft sensor was the main cause of the problem.