I had this problem on a 98 Dodge Caravan. Thing would run rough and make a HORRIBLE noise. It did have 89k miles on, however.

Turns out there was metal in the oil pan. Used a magnet and found it was Steel (Rod or Wrist Pin, Piston is Aluminum). Never tore the engine down (got rid of it with some Lucas and 60 Weight Oil... ), but the estimate was a Wrist Pin.

A trick you can try is to take a screwdriver, place it on the valve cover, then put your ear to it. Move it around and you should be able to isolate the Knocking.

Good luck, I was in for a new engine as well.


'97 Mercury Mystique GS (Not mine anymore...) Now running a Toyota Matrix XR Red, 16" wheels, Sunroof, VVT-i