This happened the other day when i went to pay for the car. The engine will not shut down with the key. All vacuum lines are fine.

I personally think it's the ignition switch itself.

This happened a few times randomly when i was going over the car, but then it would work fine.

Now it refuses to shut down with the key.

Electrically the car will shut down just fine.

Do the vacuum sections in the ignition switch go bad? Can said section just be sticky from sitting or from a lot of miles.

Would this be solved by changing the tumbler? The key does seem to stick a little. For example, when i turn it to start, it will go 1/2 way back to "run" then i have to turn it manually the rest of the way to get everything in the car to power on.