Why does my 2001 Ford explorer Police interceptor package make a grinding noise

OK so in 2016. I bought a 2001 Ford explorer 4 door police interceptor from the Kansas City police auction. I changed my oil as needed every 2000 miles, now i drove it 2500 miles doing great. then i noticed i was having exhaust in my cab. my manifold gasket was gone. so it got replaced. except the ghuy who did the job in missouri didnt replace 2 bolds over the manifold. now it was doing good. so i packed up and moved to connecticut after driving 989 miles my suv started having issues excelarating prperly. it was going up a hill at 5mph then suddenly jumped to 70 the repeat as hiolls continued. by this time i had just passed new york city on highway 84. everybody was doing 90 in a 65 and obviously my speed was pissing people off. so i kept it to a minimum and flipped my overhead lights on to was drivers of a slow vehicle. fine. then i got to my destination Bristol connecticut. it was a little bit grinding but not loud. my brother said yo bro you leaking oil. so we looked and my oil pad is leaking. first repair. then after a day my engine started grinding really really loud with an engine vibration heavy enough to knock rosie o'donnell fat ass about 20 feet. i relaized only 5 of my spark plugs are firing. OBD II didnt say anying was wrong. now i think its the bearing from lacking oil. so i stopped driving it. after carfule review i can say so far the things ive identified is

1 needs a new oil pan and oil gasket,
New spark plug wires condsidering the new spark plugs were replaced but the wires were not.
3 replacing my exhaust manifold gasket

now the question. whats the griding sound. i was told if it was bearings my engine would lock up. it starts and drives hard.

i also noticed i have a compression hose that nmeeds replaced.