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.Google+
Car Problem Reports
Ford Escort Problem With Idle Air Bypass Valve May Cause Engine Performance Problems
Ford Escort Problem
Engines Affected: 1.9L 4 Cylinder, 2.0L 4 Cylinder DOHC, 2.0L 4 Cylinder SOHC
Average Mileage: 119,500 mi (114,000 mi - 125,000 mi)
Visitor, 2003 Ford Escort, 2.0L 4 Cylinder SOHC, 125,000 mi
whenever I am at a stop sign or stop light car idle very roughly.