I have a 2001 ford Taurus a month ago I was on the highway and in died in the middle of the road a bolt got loose and fried the crank position sensor as well as broke off the teeth of the crank pulley I replaced both and it seems possibly but not for sure that a connector rod has fallen in the engine causing it to knock I put Lucas in the engine after being authorized that'd help with the knock as it did but now although its running after a short while it starts smoking all the coolants are up to par so where is the smoking coming from?
A connecting rod wont "fall" in the engine. They will snap, usually because another part failed. (Piston seized, rod, main bearings seize). Once you replaced the crank sensor, the knock you describe, does it worsen when the engine heats up? Lucas as far as im concerned, is hyped up as a mechanic in a bottle. It wont fix anything. It can however prevent some damage. As long as it is added before any damage occurred. What engine is in this vehicle? Any extra info you have will further help the diag.