I got up one morning drove my son to practice my ford explorer was fine. I stopped and got my brakes fixed and truck was still fine. I drove home when in the house for about an hour. I started my truck up and it just started knocking and shaking. No warning or anything. I am hoping that it is not the engine. There is oil in the truck. There were no warning lights on. No smoke. It still starts. It is just still knocking. Could I have thrown a rod?