Bad/weird running z31

So I have a 1984 Nissan 300zx ae auto and it’s got a very weird problem going on. last year I replaced the spark plug wires and I did the order wrong and I fixed it but I still had a misfire which I then found out a fuel injector wire broke. Well those wires ended up touching and I’ve had a lot of problems since then like if I floor it the engine like cuts out but if I ease into the load I can go to about 2200rpms, it’s a pain to start in the cold, it won’t idle very good like 6-500 rpms till dies, once warm hard to start because it misfires and back fires. Now weird thing is a while ago the alt overcharged to like 18volts and the car still started like crap but would run good as long as it was overcharged.