Ford Repair: 1997 taurus knock, freeway speeds, cam sensor

Question
my taurus at low speeds and escpecially going up hills raps loudly in the area between tranny and engine.  difficult to accelerate but no rap at freeway speeds.  What could be the cause?

Answer
what i have found on those cars is the cam sensor which is located between the engine and trans ,towards the back of intake , you would be able to hear it  at times at idle and other times with load on it , did u take oil pressure to make sure that the engine is not losing pressure worn crank bearings?, and also at times the exhaust flex pipe under car gets loose internally and causes a knock sound also