why wont my suburban idle upon start up with the heater on

the altebout rnater is new same for trhe batterie its a week old when i first start it it revs up and idles fine for a seconds then when it drops to low idle and i turn the heater on it dies only the heater nothing else makes it die

Throttle body. That is the first place I would look. If it is so dirty that the engine isn't getting enough air, then it will shut off under load. Clean it, Clean out the little hole that goes to the idle air control valve, and a big part of me says that will solve your problems. If it does not, just let me know.