Article on how to troubleshoot map sensor codes. Start with testing the sensor. Since you changed it, it's probably not the issue, but it's possible. Inspect the connector that plugs into the sensor. Is it broken/loose/covered in oil?
Code 14 doesn't necessarily mean a bad map sensor. It means the voltage the map sensor is reading is either too high or too low, which could mean a bad sensor reading the voltage as high or low, but it could just as easily be a bad ground, loose/dirty connector, or a broken or corroded wire. The tests in the article will help you narrow it down some and it will walk you through using a multi-meter to test the voltage coming into and out of the sensor, which should answer at least part of your question about how to trace the wire.
