There is a sensor under the fuel rail on the right hand side it has 2 holes to mount to a bracket with like 8mm bolts and has a nipple for a vacuum line on the bottom i will post pictures of the sensor in a few min. i would just like to know what vacuum line goes to it and what the actual sensor is. thanks in advance

2005 Cobalt SS 2.0 LSJ

 

 

Map sensor.

 

ok what vacuum line gets hooked to it? could i run it off my boost gauge line?

 

No line, that's the BARO sensor, it measure outside air pressure for some startup table calculations. It's open all the time.