Check your air idle control valve.
98 Nissan Altima Won't Idle And Won't Stay Running, What Could It Be?
Could be many things. Make sure there is gas in it. It could be a clogged fuel filter and need to be replaced. In the most extreme case it could be the fuel pump. I would also check your spark plugs and cables and go from there. Good luck hope this helps a bit. I only know this because it has happened to us a million times.
