Hi Steve.
This is exactly 100% what happened to my '87 Corvette yesterday. I had to leave the key in, disconnect the battery and turn the key to 'start' a little bit to shut off the engine after arriving at work.
After work, I connected the battery, started the car but the engine won't idle and had to hold my foot on the pedal. I risked driving it home by having one foot on the gas and the other on the break.
It's now sitting outside my house with the key stuck and the battery disconnected.
Please let me know how you finally resolved the issue as I am looking for a solution to two problems now instead of just one initially.
Thanks and regards.