CYXX-PHLI resulting in fatal crash at PHLI. The flight management computer was being glitchy from the beginning, but on descent it became apparent that I would have to mickey-mouse it if I was actually going to use the ILS. It flew me a constant 5km east of the route displayed in the cockpit, including on final approach, and almost ploughed me into the mountain beside PHLI. I then circled once and attempted to land, and was a bit too stressed to remember that I was still well about 200 knots and flaps at 10. I hit the runway pretty hard and bounced. Moral of the story is turn around and land if your computer seems to be going bonkers over a simple flight plan. I love and hate this plane, it's such a beautiful and simple one to fly but when it has a problem it has a serious problem. I'm going to go for another flight now, PHLI to PHKO to see if it happens again.