So, I had what I assumed was the typical bad starter contacts on my 2000 4Runner with 198k miles on it.

Then tonight while struggling to get contact (I would either get a click and a hum or a hum when turning the key, or sometimes it would begin turning the starter then lose connection) and a start. Suddenly the engine starting turning (Yay!) only then it didn't stop when I released the key. It went on for about 3-4 minutes before it finally stopped, during which I completely removed the key and walked away, looking to get tools to disconnect the battery. Finally the starter disengaged and it started (luckily this happened while the key was in the ON position), allowing me to rescue a cold and tired 7 year old from the far end of the trick or treat walk. Ironic that getting the starter to STOP became the desperate need after desperately wanting it to start so many times recently.

So, does this still sound like starter contacts? Or does that point toward ignition issues?

Moderators: I posted this in 4th gen by mistake as well. I didn't see a way to move the post so I pasted the text here. Feel free to delete the other post (or merge if replies and if possible) at your convenience.

Yes, it's the combination of worn contacts and plunger that caused the starter to stick on. The same thing happened to my truck and replacing the contacts and plunger fixed the issue.

Here's my theory of why, mainly worn contacts, causes the starter to stick on. There's a small and large copper contact in the solenoid that the plunger makes contact with. For whatever reason, the larger contact wears much faster than the small contact so there's a deeper grove created in the larger contact. When you turn the ignition, the plunger goes down to make a connection with the two contacts. Because they are at unequal levels due to the uneven wear, I believe the plunger can sometimes get wedged or cocked between the contacts and get stuck. It's the only thing I could come up with that made sense to me. Maybe somebody else has a theory on this but I do know replacing the contacts and plunger fixed the problem.

BTW, I now keep a channel locks inside the vehicle in case this ever happens again so I can quickly pop the hood and twist off the negative battery cable to stop the starter.

Here's a video I made for this repair. I hope it helps you out.