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.
Confusion and sleepiness may occur in the last hours. Secretions in the throat or the relaxing of the throat muscles can lead to noisy breathing, sometimes called the death rattle. Repositioning the person, limiting fluid intake, or using drugs to dry secretions can minimize the noise. Such treatment is aimed at the comfort of the family or caregivers because noisy breathing occurs at a time when the dying person is unaware of it. The death rattle does not cause discomfort for the dying person. This breathing can continue for hours and often means that death will occur in hours or days.