1993 Acura Vigor Ignition switch?

Electrical problem
1993 Acura Vigor 4 cyl Two Wheel Drive Automatic

Hi.
I have a 1993 Acura Vigor LS with a 5 cylinder 2.5 Lt Engine.
A couple days ago, I started it and when my key turned back after it started, the engine died. Now when my key turns back the car dies. I have checked that my fuel bar is sending gas, there are no leaks. My fuses are all good, so the fuel pump shouldnt be stoping.
My question is, how can I tell what exactly I need to replace. I suspect its my ignition switch, however I could be wrong.
Any help or info is great.
Thanks.