On the 2.7L V6 and 2.4L 4 Cylinder, a defective exhaust gas recirculation (EGR) switching valve may cause an intermittent rough or unstable idle engine.Google+
Car Problem Reports
Hyundai Sonata Rough Idle Due to Faulty EGR Switching Valve
Hyundai Sonata Problem
Engines Affected: 2.4L 4 Cylinder, 2.5L V6, 2.7L V6, 3.3L V6
Average Mileage: 104,742 mi (16,000 mi - 200,000 mi)
Visitor, 2004 Hyundai Sonata, 2.4L 4 Cylinder, 37,000 mi
Rough idle when stopped. Car shakes a lot.
engine idles rough when in drive but not in neutral
engine light indicated need to repalce EGR valve. Did so a a week later it says the same thing again and idle is rough again. Why????
Visitor, 2001 Hyundai Sonata, 2.4L 4 Cylinder, 110,000 mi
Rough idle, lack of acceleration at times, and poor gas mileage.
Visitor, 2003 Hyundai Sonata, 2.4L 4 Cylinder, 45,600 mi
Rough and unstable engine. Feels like gas is choked from engine or loose battery wires. Then car takes off. Scary! Not fixed yet
Visitor, 2002 Hyundai Sonata, 2.4L 4 Cylinder, 150,000 mi
Rough idle and engine seems very rough while accelerating from a dead stop. Runs well at cruising speed. Only seem rough when the engine is under load.
Roough idle, jerks a little when driving, began to stall. Will change Throttle Position Sensor and see what happens.
Visitor, 2004 Hyundai Sonata, 2.7L V6, 40,000 mi
Driving down the road and all of the sudden the car looses speed and the gas pedal is non responsive while the engine light comes on. Causing you to pull over immediately and it pretty dagerous because there is no warning and a sudden thing.
Visitor, 2005 Hyundai Sonata, 2.7L V6, 74,353 mi
Random misfires, rough idle, Not yet repaired
Visitor, 2004 Hyundai Sonata, 2.4L 4 Cylinder, 166,000 mi
check engine light