My Mazda is a 1996 B4000 4wd. I tried to get my truck inspected, but trouble code PO34 showed up and this being the reason my check engine light is on. Also, the ready codes required for it to pass inspection were not all ready. The O2 sensor was not ready, as was the HO2, the EGR, and the catalyst were also not ready even after drivig it for about 20 miles. Also, the temp gauge quit reading correctly the same time the check engine light came on. Any suggestions on where to begin?

This is an OBD code for MAP Sensor Out Of Range.