Mitsubishi Repair: knock in engine, engine detonation, eclipes

Question
i just purchased a 1998 eclipes from a girl i know.. i payed only $200 for it and the body and interior is in perfect condition but there is a knock in the engine. some one told me that it could be a knocking sensor. Also i was told that the head might have to be rebuilt or that i bent a rod.. i dont have any loss of power so i dont think its a rod and i havent found any metal in the oil so know im confused please help

Answer
The knock sensor won't make any noise. It is an inert device screwed into the block and doesn't move or contact anything. It simply detects engine detonation and informs the computer via a A/C voltage. You can pull (and properly ground) each plug wire individually and see if the knock goes away. The one that allows the engine to stop knocking is the cylinder with a bad rod bearing. A bent rod is also highly unlikely unless you have sucked water.  You can also use a large screwdriver and place the metal end against the block and the other end against your ear and listen for the noise, the closer you get the louder it will be.