Gauge pressure transducer to Arduino

So I bought a Honeywell pressure gauge pressure transducer, with the following datasheet:

The thing is that I want to measure pressure in a small pressure tank, but first I tried to read some voltage out of the sensor and It printet 4.66V? The pressure sensor was not connected to anything, only the Arduino.
My code was:
int sensorValue = analogRead(A0);
float voltage = sensorValue * (5.0 / 1023.0);

I thought it would print out 0V when no pressure was applied to the sensor?

The pressure sensor has eight pins. How were they connected?

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If you look at the transfer function graph in the datasheet you will see that the span is from 10% to 90% of supply voltage. So if you are using 5v, 0 would be .5v and full scale would be 4.5v.
This is a pretty common voltage span on a lot of pressure sensors.
I also noticed that some of these sensors are 3.3v and others 5v. Make sure which ones you have.
It looks like they only use pins 1,2 and 3.

1 v supply
2 v out
3 gnd