Not an erratic idle like a dirty throttle body gives you. That goes up and down when the AC compressor kicks on, and can send the idle down to 300-400 RPM and stall the engine out. Then it overshoots when the compressor cycles off.
death rattle. a sound produced by a person immediately preceding death, resulting from the passage of air through the mucus in the throat.
A death rattle may occur when a patient is near death and experiencing trouble breathing. One technique used to manage a death rattle is to reduce the amount of fluids a patient is given. People near death often report seeing a bright light.