I was driving a my car about 90 miles I noticed that the oil light started to flicker on and off but i was going to try and make it home where I had oil, I stopped to get gas and when I cranked it it started making a horrible rattling, knocking noise coming from the engine area. I stopped and got some oil treatment, engine repair stuff and put it in. The car makes the noise the same all the time whether I am accelerating, driving at a constant speed, or just idling. I have not noticed any loss in power or any problems with how the car drives. I drove it home, about another 30 miles, and left it sitting over night. The next day when I cranked it it wasn't making any noise so i drove the kids to school. After about 5 min or so it started up again. I cranked it again later and it did the same just idling, it was fine for a few min then started with the noise again. The noise is hard to pin point exactly where it is coming from, it is just some where around the engine area. It is a 1997 Ford Taurus station wagon. Does any body have any clue what might be wrong with it, and how much it will cost to fix, or is it just about dead.