I have a Greddy ProfecII EBC and at idle what is the reading supposed to be? I looked up vacuum, but that doesn't seem to be what it is measuring.

In PSI mode, I get -76 (I think it's actually -7.6, since when it displays 190 it actually means 19.0), and in metric mode I get -.5(100x kpa).

What readings are these of??