I Need help plssss

hi i have a 99 acura integra gs , i have changes the timing belt , water pump , spark plugs , and wires too, but last 2 week a problem started, and it happens some times , i get to the stop sing or light and the car just dies, it start back up but now is doing it more often, whar cand this problem be? fuel pump mayand be? and after this happens the car wont pass the 3.500 rpm, but when the engine cools down it come back to normal. i really need help pls