I had a similar problem years ago. It was an electrical issue in my steering column. After it was fixed, I was advised to "lighten the load" on my key ring.
However, a friend of mine also had the same issue and it turned out to be his alternator. Yet another, it was the fuel injection and fuel pump.
So, it's a toss up. Just make sure you get it checked out ASAP before you get stranded at a most inconvenient time!
May I suggest you "call" a few mechanic/garages first to get numerous ideas as to what might be wrong BEFORE you take it in to be repaired, that way you and your vehicle are not taken for a "ride"...
Good luck and may safety follow you!