I have a problem when running a 3d tool path, it goes just fine then for no reason it will move the starting point. And then the project is just a scrap of lumber, has anyone else had this problem?

Can you attach our xml and also the code you are having issues with and say roughly the line number in the code where the problem appears.
Hood

Sounds like your machine is losing steps and losing position. Try lowering the acceleration by 50%.