1997 Oldsmobile Cutlass engine cuts out when hot

i have tried all kinds of things but nothing seems to work...whenever the engine gets warm it cuts out and sometimes stalls whenever i accellerate or go up a hill but when the engine is cool it runs like almost new. i've had the temperature sensor replaced, the computer replaced, a new alternator, new fuel filter, and now a new catalytic converter put in and nothing has changed at all