My 550 has a issue where randomly when turning the key to start everything happens (dash lights, radio, etc) except the starter doesn't turn over. Sometimes there is a delay of a few seconds, others there's absolutely nothing. If I wait 15mins and try again it starts normally. Has been doing this for over a year now, Nissan service were useless (we can't reproduce the issue). I'm getting concerned now as I am going camping next week on Moreton Island and the last thing I need is to be stuck somewhere isolated with a dead ute.