[Formulalt1]

That tune will stay in the PCM's memory til a new tune is uploaded though and even so. Most tuning uploading software requests you to save the prior tune to a file before it erases it and then uploads a new tune. You can also just supply power to the PCM without the engine hooked up though and change the settings.

Edit- Also, just a suggestion and others sometimes disagree but I would find a 94 - 95 PCM and use that for tuning. With a 94 -95 OBD 1 hybrid you can upload tunes and change settings yourself with software (some of which is free). That way if you make a change as some point you don't have to bring the car somewhere. I change minor stuff in my car but when I change stuff that will need to have things remapped I just email or call Bryan and he emails me a new tune within a day and 2 pins/15 minutes later I am good to go.