transmission stuck in high gear on 1991 Buick Century

when coming off highway, and coming to a stop at end of ramp, car seems to want tokeep going, but when apply brakes to stop, engine cuts out...restart, runs fine..put in gear and kinda jumps then stalls...whats causing this?
any info would be greatly appreciated

Asked by for the 1991 Buick Century
the tcc is stuck, when the car cools down its probley fine till it gets back to hwy operating temp,unhook the tcc will fix this and not harm the car.