1990 quad 4 cutlass, knocking

Hello, I have searched the threads and can not find what i need so i am asking for help...My 1990 quad 4 cutlass supreme, vin "d" is knocking. I pulled up at my moms house and checked the oil and it was about half a quart low, so i topped it off...i started the car and the check engine light came on, so i drove it around the block, it would make a faint tick and then stop, and then the engine light went off. I parked the car and when i came back later that night to leave, i started the car and got about a mile down the road and the ticking came back but this time it grew stronger untill it sounded like something was hitting under the hood, the car lost power, so i pulled over and turned the car off. we had it towed to my house the next morning. Now when you jump the car it starts right up but knocks. after the idel comes down it will stop knocking, but when you give it gas it starts again....this has been over a year and a half ago...i really love this car because it was my first car and dont want it to go to the junk yard so could someone please help me....thanks alot

Sounds serious, but from this desk I cannot offer a definitive diagnosis, someone has to listen to this on site, probably serious internal issues based on your description.