Is it ok to blow into a pressure transducer to make sure it is working properly?

  DO NOT DO THIS!

It is very possible that by blowing into the ports of a pressure transducer you could damage the internal components, especially if the transducer has a lower range. If you want to check and see if the ports are working properly, you can rapidly tap the port or gently pinch the tube. 

It is important to note that for unidirectional differential pressure sensors, this must be done to the HIGH port only.

You can also check the zero of the differential pressure transducer.

You can do this by opening both ports to atmosphere and checking if the reading goes to zero. You can also place a jumper tuber over the high and low port with a tiny pin prick