1997 Chevy Lumina 97 Chevy Lumina, 3.1

The problem started 2 weeks ago I would be driving and the acceleration would let up when my foot was still on the gas, but would only last for a few seconds and would start to accelerate again. I thought nothin of it and put some carb cleaner in it, and I seen I was a quart low on oil, so I also put that in. A short while later the car did it again and then it compleley died, at which time I tried to restart it and it will start after a 20-30 seconds of turning the key but it is very hard sounding, extremly loud, and if I dont stay on the gas pedal pumping it the car bogs out and dies, also if I try to put it in gear it dies. It sounds horrible, I don't hear a rod knock at all, and the car did not over heat. Is my motor junk, is it the timing chain, cadilac converter? I'm so LOST