twin fd3s

ok heres the my problems i my fd was running great. til one day i went to start it up and it did. the car starts great but as i accelerate it stumbles unless i acceerate slow till it get 3500rpms also when the car is warm if i acelerate let off then go into to it again the car the engine just turns off . ok now the car is warm once it dies it tries to start but it will not i have changed the fuel pump and the filter and nothin still the same if anyone can help that would be great thanx