Motor doesn't shut off when key is in lock position and removed

[jawja jim]

89 L auto is not shutting down when the key is all the way to lock position and removed. I have to unplug VAF to shut it down. First happened after after I had flushed cooling system and changed the oil and cranked it up to let the oil circulate to recheck level. I turn it off and pulled the key and it kept running, 3 or 4 times. Took it out to gas up it and about a half block from the house, it slowly died. Recranked easily, idles a minute or so and I turn the key off and it stopped normally. Cranked again and stopped again with key off. Fired it up again and continued on to the gas station, where I cut it off normally and I filled up. Drove back home and it would not shut off.
I replaced the ignition switch and key switch with one from my 89 LX parts car and it's still doing the same thing. Searching on this forum with all phrases I can think of has yielded nothing, but that is pretty standard for my search history. Any suggestions?

[WmWatt]

My first action when something like this happens is to spray WD-40 into the ignition key hole and work it in with the key.

[LordOfTheCars]

unplug the ignition switch and tell me if the motor shuts off.

[jawja jim]

While removing the column cover and brace to get to the plugs, I noticed I hadn't tightened the screw that holds the ignition switch to the key cylinder, which I had also replaced. At least my head got back in a position to see my "screw" up, and tightening it seems to have done it . I've put it through many on-off cycles and it hasn't missed yet, but yesterday's fake out is going to keep the cover off for a couple more days. Thanks.

[LordOfTheCars]

While removing the column cover and brace to get to the plugs, I noticed I hadn't tightened the screw that holds the ignition switch to the key cylinder, which I had also replaced. At least my head got back in a position to see my "screw" up, and tightening it seems to have done it . I've put it through many on-off cycles and it hasn't missed yet, but yesterday's fake out is going to keep the cover off for a couple more days. Thanks.

I have seen the problem not be electrical. I built a 440 Chrysler for the quarter-mile, the guy put it in a Dodge Challenger. He never ran regular unleaded in that motor again. It was tunning via pre-ignition.(Quite well I might add.) cooling the radiator and misting water through the carb got it to shut down. The clue was key off and pulling the coil wire and it didn't skip a beat.