So my 4.0 V6 Mustang got into a accident and it was hit from the front of the car and so the airbags activated and everything but now that I'm trying to fix it gas doesn't want to get to the motor, what could it be ?

 

The collision has probably tripped the fuel pump inertia switch. It's a safety item that was installed to prevent a fire if an accident causes a fuel leak. There's a button to the front of the hood opening handle behind the driver's side kick panel. If you can push it in, it means the FP inertia switch has indeed been tripped and doing so will get you going again.

 

Then what would I have to change to get it running again ?

 

Nothing unless there's a component that's been pushed in far enough to interfere with the engine.

 

Ok so we were able to get it started and all but now when we turn it off it dies out completely but we already fixed the terminals and the battery, what could it be now ?

 

You might want to check the engine grounds.