Raisealilhell

Just bought a 92 Acura Integra. Ran great until yesterday. Started sputtering and and wanting to die. Ever worse when the heater, headlights and rear defrost are on. Replaced alternator thinking it was it. Nope still doing it. Just put new spark plugs in it too. The rpms are all up and down. Gonna go and tighten the fast idle control bees wax ring thing and see if that helps but I don't see why having the accessories on would effect that. Any ideas?