"I had a faulty ignition switch that was sticking, causing the solenoid to continue to stay engaged."
I am experiencing a similar situation = the starter motor keeps cranking regardless of whether the key is in the ignition switch or not, and keeps on cranking until I disconnect the battery.
the engine itself will start ok (even though the starter motor is still engaged) - I do not get "silence" or "just a single click" etc.
My question = how can I test if this is just an ignition switch problem ?
many thanks for any advice.