I would check for a plug wire problem.
The fuel injector will be turned off if a misfire is detected. This is often the reason for one injector to be shut down.
I wouldn't be surprised that the controller can't be moved once its learned the car. All units after 98 would be I'm not sure on how DAS interacts on a 97.
Bosch Master, ASE Master, L1
33 years MB technician