So when I got my car it ran like a top it’s a 1990 z24 with the 3.1l and it drove fine until I got near my home and then all of a sudden it basically went into limp mode, giving it gas was sluggish and then when it slowed down almost to a stop it started jerking and hunting for idle and then stalled. I noticed that there was clunking inside the cat so the cat blew up and so I just cut it out. ever since I got it home I will start it up and it will run fine for about 30 minutes then the rpm’s start to bounce and then eventually it hunts and hunts and then dies. I have replaced my crank sensor, idle control valve, pcv valve, cleaned the maf, replaced a coil pack that wasn’t firing properly, and replaced all the spark plugs and wires. I am completely lost.