2009 cobalt ss turbo, it is tuned and will peak about 23-24psi and hold 19-21. Where does the baro on my rpd get the value for barometer from? I know the sensor works since whenever I clear the code the barometer shows a reading until I shut the car off, then it triggers the engine light again not letting my car hold more than about 12 psi and a flutter when I let off. I heard from one person it gets the reading from the map sensors? I know one map sensor is on the intake manifold at the front of the engine, I can’t seem to find the other one? Another said I need to replace my ecu since that’s where the reading come from, does anyone have a for sure answer what would trigger p2227? Also could a bad tune cause this to be triggering codes?