Did you ever get this figured out? It sounds like your ecu might be running in safe mode. You should check to see if you are throwing any codes. Some codes dont always turn the check engine light on and will put the ecu into safe mode. A blown knock sensor is one common problem that will cause the car to stay in safe mode.
I would also do a search on www.mr2oc.com . Pretty much anything you could ever need or want to know about mr2's can be found somewhere on those forums.