There are a number of things that could cause a problem like this. Some possibilities could be:
- Ignition switch. (common problem and may be under a Recall. Check with the dealer on this. Even if not covered under a Recall that could still be the problem as the same flaws affect many vehicles outside of the Recall VIN range)
- Main relay. (also a common problem)
- Failing fuel pump.
- Ignition module.
Numbers 1 through 3 are sort of intertwined in a way. Failing fuel pump (or clogged fuel filter) over time causes the pump to use more electrical current (heat) which means the main relay suffers more and since the ignition switch powers the main relay it also suffers.
For a free code scan drop by an AutoZone, Advance Auto, Checkers, or a similar outfit and have them check the car. It’s free and only takes a few minutes. This might at least weed out some things other than what I listed and give you a starting point.