The 3.2 4m41 non-common rail engine has an idle butterfly that uses a vacuum diaphragm to close the throttle butterfly about 95% in order to reduce noise and vibration at idle.

This mechanism only kicks in when the engine is at operating temperature, and ill adjustment can create stalling and/or driving/starting issues at idle when warm.

Blocking the vacuum pipe that feeds that diaphragm will throw a CEL.