All my power works when i turn the key to on position but truck does not turn over or start. I just replaced starter, and alternator just a couple months ago as well as battery is testing good. If i play with it by turning the key back and forth it will eventually turn over and stay like that for a couple of cranks but then will randomly go back to not starting. Does any one know what is causing this i think it might be the ignition switch.

 

YESS........S.
May be the actuating rod or the switch.
Good luck.

 

Just for kicks tilt the steering wheel so the colum is straight (not up or down) then try it.
If this works it is most likely the acuating rod that Bluegrass mentioned.