If the throttle plate is prevented from closing, thereis an increase in idle speed as well as slower than normal deceleration, whichoccurs without prior warning and could result in an accident.
The crankcase ventilation system, vented into the intake tract of the engine at the bellows boot ahead of the throttle housing, allows warm water vapor from the crankcase vent to condense and freeze in the colder bellows boot when the ambient air temperature is 15 degrees Fahrenheit or less. The build up of ice can dislodge and move into the throttle housing, preventing the throttle plate from fully closing when the driver releases the gas pedal.
Replace the throttle housing with a version containing a modified heating system along with rerouting of the cvs hose. This will prevent ice build-up in the intake tract.
