Today I turned the key to my 86 560sl off and the engine kept running.
I turned the key many times back on and back to off but no luck at
killing the engine.  I drove the car home and when in my garage where I
could look and investigate things it of course turned off the first
time I tried. What luck!  Well I can only guess that it was the
ignition switch that had kept the car running.  Can any one tell me if
there is any relay or secondary component to the ignition switch that
could keep the engine running while key is in off position or should I
just start looking for a new switch?

Thanks Bruce Buchanan