Engine Stalling and/or Hesitation on Acceleration due to Faulty Idle Air Bypass Valve on Mercury Mystique

Problem Description and Possible Solution

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.

Problem Data
RepairPal Verified
Average mileage: 170,787 (110,000–235,675)
Exhaust & Emissions affected: 2.0L 4 Cylinder
2 model years affected: 1999, 2000
18 people reported this problem
Viewing 1 - 3 of 3 comments
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!
stalling, rough/erattic idel
cleaned iac valve with carb cleaner
Idles rough, doesn't stall ,just rough idle