Why is my suv dying on me?

About one month ago my 1995 Nissan Pathfinder 4x4 with a 3.0 engine started dying on me I put new spark plugs and wires on it the problem stopped up until a few days ago now its dying again it only dies when idling, coming to a stop (when engine brakes and rpms are getting low) it doesnt die when driving it today I put new rotor cap and button on it at first I thought the problem stopped but it hasnt its continuing to die what is the problem? do I need better plugs? or is it something else? I dont reall think its the alternator because when its starting to die i turn off everything that has power going to it like radio lights and heater and it doesnt change anything or make car idle better. what do i need to do?