1995 Eagle Talon and it will turn over but wont start what might be the problem?

in this case i had the same promblem on day i parked car then went to start it would not start i chaded the coil pack no luck chaded the fule filter no luck i cahged the ecm and is stared rigth up then now is want to die on me sometimes when driving if i where u chage the fuel pump and check all relays