I have a question is the gas filer or check valve or what ever it is on the map sensor vacuum line is it a one way valve like the check valves? Because I checked mine just like you check the check valves and air goes threw both sides is this right or is it only suppose to flow air threw one side?

 

its just to keep the fuel away from the map. air goes both ways

 

It's a filter, not a check valve which is why you can blow through it both directions.