Bad Ignition switch?
The reason I say that Is cause that is the switch that controls almost all of the electronics in the entire vehicle. And you say that if you hit the steering wheel it cuts off. The switch is on the column so honestly I think this is the problem.
To test in a non technical way, crank up the engine and let it run for about a minute taking a small small hammer or the handle of a screwdriver, lightly tap the switch, the Column, the steering wheel, all in between. If it dies on the tap. Most likely theres your problem.
That's my redneck solution for you.
If you have a meter and you know electronics, pull the plastic panel off and check voltage of the switch off to ground, should have 0vdc. When on ~11-14vdc depending on your alternator and if your running or not.
Wanna still play around with it? Tap it then while the meter is attached check readings in on position. Record findings.
