like the title says, tonight i was driving on the hwy doing about 55 not even playing around with the car. I heard a loud wining sound for a split second then i lot of metal against metal and the car instantly shut down.. Coasted to a parking lot, popped the hood to discover my timing belt was extremely loose, looked down the timing case too see my tensioner just sitting there broken off the engine. This is a 2jzge that i NA-Ted, I recently rebuilt the bottem end like 3 weeks ago. What would cause this too happen??!!