Sn owo41676 jul 2004 v6 mpi the motor is not advancing timing as it should at idle it is sitting smack on top dead 0 deg and is only advancing at set points in the rev range. Timing was checked with a digital timing light ,balancer has not slipped. With light on timing marks they do not dance around as it should trying to find optimal timing. Boat will run the same with knock sensor disconnected or connected it is a new censor . I have tried the knock test on block with hammer and it does not pull timing. Motor has been this way as long as we have owned it. Ignition has been given a complete overhaul as has the fuel. Distributor is set as per manual on the 6 mark all timing marks have been checked and re checked I know timing is non adjustable. Is there any fail safe in the ecm that would revert to a safe timing curve with out guardian mode going of ? Boat starts well it has a slight flat spot on hard acceleration and is lacking a bit of hp but overall it does what it needs to we only ski and wakeboard so the flat spot is annoying. Getting to a dealer is difficult but not impossible but they don’t work on I/o so are not interested in sea trials or fault finding. I can get it on their scanner if I have something to check. thanks in advance