Car won't shut off...Help!

I hate to say this but you easily could have "hidden meltage" in your ignition harness. The fact that you "fixed" it might mean that you "wiggled things" just enough to "unmake" the unwanted connection.

(The ignition circuit is NOT FUSED other than the main fuse link, so this means EG that something like a grounded brush at the alternator could have "smoked" the ignition harness and heated it up. That is, the "run" feed)

DO YOU HAVE any wiring modifications/ former hacks/ ragged wiring that should "ring a bell"

Some things to consider:

Mentioned conductors melted in the harness
Some hack someone added a tach and got sloppy with wiring
Bad ignition switch. New does not mean "good"
Testing with light and meter IS YOUR FRIEND

If you can make the problem reappear, rig a good bright lamp that you can SEE such as an old tail/ turn bulb and socket. These are VERY handy sometimes, as you can wire them different ways

"Rig" the test lamp to the IGN1 (run) feed and start wiggling things..........the bulkhead connector, the harness in different spots, the switch connector, and the key/ switch itself.

SINCE THESE VEHICLES do not have an "idiot lamp" charge lamp like GM, there is very little possibility of factory wiring having a "feedback" condition which will trick you