Map Sensor.....
 

Hey guys gotta question.....u know that hose that connects between your MAP sensor and the manifold.....well that small filter that is inline between the MAP sensor and manifold is it a filter that can flow in both directions or is it a one way check valve.......? I inspected mine and it was flowing in both directions....but when I shook it around a little I could hear something rattling around inside....so I figured it was a one way check valve that went bad....so I replaced it with an after market 1 way check valve. and installed it so that air would be flowing away from the sensor(so it would read vacuum)... Car seems to run ok with it. dunno..... So maybe u guys might..... Thanx.... Tony

Nope, it's just a filter. The arrow is so that the dirty side of the filter is always the dirty side. I can't imagen that a check valve would allow the car to run well. How would boost, or Vacuum be read at the same sensor. Strange