If you experience difficulty starting the engine when cold, stalling at idle, or hesitations during acceleration, it may be the idle air bypass valve. This valve helps the vehicle idle steady when the accelerator pedal is not pressed.
Car Problem Reports
Mercury Mystique Problem With Idle Air Bypass Valve May Cause Engine Performance Problems
Mercury Mystique Problem
Exhaust & Emissions Affected: 2.0L 4 Cylinder
Average Mileage: 157,809 mi (110,000 mi - 200,049 mi)
Visitor, 2000 Mercury Mystique, 110,000 mi
stalling, rough/erattic idel
cleaned iac valve with carb cleaner
Visitor, 1999 Mercury Mystique, 130,000 mi
I'm having problems with starting car in mornings. The car will crank but not turn over. I've brought the car to 2 different mechanics after repairs were made w/ new fuel pump, radiator fluid changed, new sensors, and finally a replaced air control valve. After the new valve the car ran fine for 3 days, and then the problem started all over again. The car runs fine & restarts great after it is warmed up. But, the mornings it will not start. I'm about ready to give up!