hey guys a couple days ago i was driving back from work and all of a sudden my rpms drop to 0 and i coast into a target parking lot, my low oil light has been on for a while even tho there was oil in it, i had already got a new sending unit and was gna change that, well i let it cool off because it got really hot and then limped back home. yesterday i changed the oil and put in the new oil sending unit and noticed i only had a quart in the entire pan but i know there was way more in it to begin with. what came out had metal specks in it and i know thats bad but now after the fact i tried to drive it around the block and immediatly starts overheating and starts knocking at idle and over 2000rpms, i have no idea where to start or what to check, it has 143,000 miles on it. any advice would help thanks