Okay, here's new one that I bet nobody's read before:

The other day, I went to start my SC300 5-speed with 140K miles. I momentarily turned the ignition key against the spring into the 'start' position. The engine started right up, but when I released the key, the starter CONTINUED TO CRANK the engine! It was clear the starter was being spun by the running engine. Thinking quickly, I removed the key from the ignition - yet the engine still CONTINUED TO CRANK! Shifting into emergency 'save my battery and starter' mode, I yanked open the hood and pulled the negative cable from the battery, and then waited a few minutes. When I reconnected the battery cable, everything seemed normal, so I tried starting the engine - and that started normally, too. That was three days ago, and the car's been fine since.

My question: It this definitely the starter solenoid getting stuck in the 'on' position, or could it be something simpler, like the starter relay or even the ignition switch?

 

Well, that's a scary scenario!

It could possibly be the relay or ignition, but 9.9 times out of 10 it's the selenoid that's causing the trouble.

 

or 99 times out of 100... whichever you want to hear more...

but, yes, i concur - you've got a starter solenoid sticking, go get you a new/rebuilt one and slap her in there...

chances are you'll never be able to duplicate it when you want to, so getting it diagnosed would be next to impossible...

 

i ran into this problem yesterday. except i removed my negative battery terminal for an hour and then i reconnected it and it just started to crank again nonstop.. going out to buy another starter today. anybody happen to have any starter DIY's?