1994 Toyota T100 truck

I have a 1994 toyota t100 truck. The battery worked lose and arced and burned up the ground wire. I replaced the battery. Now it starts great but it dies when you try to put it in gear or turn on the air conditioner! What could this be?

Maybe a foregone conclusion, but you did replace that ground wire, no? I’d check to make sure you have a decent ground anywhere - and not just to the battery but also to the frame and body.
Since there was a path to burn wire up, it could very well be that your positive wire may need some TLC as well.

The only way the ground wire got burned up is if the positive post shorted to ground…It’s as if you connected jumper cables backwards…The entire under-hood harness needs to be checked for damage/burned connections…Start from the battery and work out…

If only the positive post came into contact with a ground when it bounced around, it is possible that only the neg cable to ground got fried, but you need to be extremely careful that nothing else did. I agree that your neg cable may well be fried. You can bet things got mighty hot in that area.