My 93 Impreza has been giving me problems for the last 3 months. When i'm driving for awhile it starts to spit and sputter and will just lose all power and shut off. I can usually start it back with no problem but at times it will take a few tries. I changed the Fuel filter, Fuel pump, spark plugs/wires, air filter, and PCV valve. I was wondering if anyone could give me any suggestions of what i might need to change next to get rid of the problem?