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.
Type II Death Rattle. When anticholinergics are used consistently, yet the death rattle continues, there may be another underlying cause. These cases have been referred to by Bennett (1996); Morita, Tsunoda, Inoue and Chihara (2000); and Wildiers and Menten (2002) as type II death rattle.