hate to say this but that is almost for sure a spun bearing that is causing low end rod knock, your description is almost perfect of it. if you are going to keep the car you have some options, the first one is a new/used 2.5(not worth it IMHO) second is a new/used 3L(worth it, and costs about the same)

if you must now get ride of the car, i am sorry to be the bringer of bad news, aslo if you plan to get ride of the car PM me so we can talk about me getting it

98.5 Black SE ATX S&B filter, SVT MAF, optimized SVT TB, mesh grille, removed orange reflectors, painted rear reflector, gutted pre-cats, optimized SVT LIM, 19lb injectors, resonator removed cant afford an svt but lookin for 1 in nc