Why did my car cut off while driving an then i cut it off an tried to crank back up it just turning but wont start

Sounds like the fuel pump quit although it could be other things as well. I'd start there though. Turn the key to the on position. You should be able to hear the pump run for a few seconds as it builds up pressure. If you hear it, the pump is not your problem. If you do't hear it its the pump or something related to it.

My 2008 Pontiac grandprix will cut off sometimes while sitting and sometimes while driving then starts back up what could it be

It could be a bunch of things. Make sure electrical connections are tight. Scan it for trouble codes and check fuel pressure. Those are usually good places to start.

Yea idk if you know anything about wiring but that could be your a huge part.. Where you from? Is it your DD??