2006 mustang gt

Maybe spray some starting fluid in the throttle body while someone is cranking. If it catches, it would be a fuel problem. If it still doesn't catch, it would be a spark problem. If fuel, check fuses, inertia switch (if it has one), relay, filter and pump. If a spark problem, check crank position sensor and maybe cam position sensor. Does it ever sound like it is trying to catch? Auto or Stick? Have you tried to pull codes?