I have a 1994 Camaro Z-28. After I drive it for a few minutes, I can
only turn the ignition switch to the "off" postion, but it will not
turn fully to the "lock" position so I can remove the key, until it
has sat for an hour or two.  After an hour or so, I can reach through
the drivers window and easily turn the switch and remove the key
without touching anything else.  This happens using either of my keys,
and if it was a linkage adustment problem, I would think that should
not happen after justing sitting awhile.  It acts like a vacuum
diapham or electrical solenoid is returning to it's normal position
after the vacuum in reduced, or electrical solenoid has cooled down
and retracked.