Hello everybody. First time car owner here. Recently I took my car to get its emission test and the test revealed a P0106 code. I asked a car savvy friend of mine what could be wrong with it and she suggested a probable vacuum leak. I discovered that the vacuum hose that goes from the brake booster to the intake manifold was completely ruptured. I went ahead and replaced it, but after resetting the OBD and driving it for ~40 miles the light came back on. I drove to Autozone and after having the check engine light checked the same code came up. What should I do? I have replaced the spark plugs, air intake and pcv valve. I am not sure if the previous owner/owners cleaned or replaced any other component of the emission system.

 

You can always type the code into a google search and find out what it means. PO106 means trouble with the Manifold Absolute Pressure Sensor. It does not mean "vacuum leak" or "bad MAP sensor".
In older Proteges and possibly yours as well the MAP sensor sits on the the firewall, passenger side. There is a vacuum tube running down from the sensor to the back of the intake manifold. This tube could be broken or the nipple on the intake manifold could be obstructed. Poke through with a piece of strong wire.
In older Proteges they used to call the thing "EGR Boost Sensor".
I found this picture of a '99 model. they call it EGR Boost Sensor as well.