Carlos

You've probably already checked this but when my plugs fouled, it did exactly the same thing. I know the symptoms aren't exactly typical of fouled plugs, but when mine did what you are describing, that's what it was. I have had plugs foul before on my old merc and it acted totally different than w/ the HPDI. Not sure if the HPDI can detect the misfiring and it cuts itself back or what but that's what it did. I hope your issue is as simple to resolve as mine was.