Pressure sensor not working

Hi, I am using a freescale semiconductor MPX4250AP pressure sensor for a project but somehow it doesn't work. I am using the arduino mega board and only using the 'analog read serial code' in the examples. (I am also using arduino 1.5.2)

/*
  AnalogReadSerial
  Reads an analog input on pin 0, prints the result to the serial monitor.
  Attach the center pin of a potentiometer to pin A0, and the outside pins to +5V and ground.

 This example code is in the public domain.
 */

// the setup routine runs once when you press reset:
void setup() {
  // initialize serial communication at 9600 bits per second:
  Serial.begin(9600);
}

// the loop routine runs over and over again forever:
void loop() {
  // read the input on analog pin 0:
  int sensorValue = analogRead(A0);
  // print out the value you read:
  Serial.println(sensorValue);
  delay(1);        // delay in between reads for stability
}

What happens is that all I see in the serial monitor is 0.

I am fairly sure I have connected it correctly:

Pin 1 - analog input 0 Pin 2 - ground Pin 3 - 5V see attachment for picture

The weird thing is that when I switch the ground and 5V wires, all I see is 1023!

It was working before but somehow stopped! I have done nothing to damage it.

Is it faulty or am I doing something wrong?

Thanks

First do measure the sensor's output with a voltmeter. You have to read about 1.8Volts.