1. G.V 1.6l 2004.
2. Tester (OBD2) is showing EGR (code 0400).

3. Additional symptom:Fast accelaration couses an strangulated effect(a very short delay), as an intermmidiate reaction.

3. What are the common problems that cause this code ? What should be done for fixing? (pls' list them fr. the easyest to the mor dificult)

4. Where's the sensor's location? the connector?
What are the right voltages ? in idle? medium/high motor speed?

I don't know how much they have changed over the years, but my '96 1.6L 16V OBDII threw an EGR code a while back.  The EGR had a steel tube running from the valve to the engine.  The end at the engine and the port that it connected to was plugged with carbon.

I took the tube off , ran a wire through it, cleaned out the port with a wire brush and carb cleaner, and it cleared the fault.  Didn't need a new EGR valve.