Engine Rattle .... Help! :)

hey, it seems like to me that, you might have rod bearing knock . i hade the same problem with my supra. and the thing with starting problem my supra does the same thing, you can hold key to the on position wait 5 second then it will crank. i dont think its a bad connection, my friend 92 does it also. i hope i helped. also check your engine grounds, if the engine grounds are loose it can also cause the engine to rattle or shake the car as if it had a cam.