injectors leaking down into cyl. after shutdown

ive got an 85 380 se and was told by a reputable shop that the injectors were leaking down because i told them that when i cranked it up after it sits a while it bounces around for a couple of seconds (5 to 7 sec) and returns to a normal idle this happens when it cold and hot what are the posible problems and can they be fixed by a do it your selfer thanks in advance