the flapper is part of the EGR/Anti Shudder Valve - least that would be my interpretation of the analysis.
Pull up on the large clip for the upper intercooler hose, Also remove the spring clamp from the other end of the hose and remove the pipe. Peer into the inlet with a bright light and check for obstruction. If you see anything i would recommend removing the three hex bolts securing the Anti Shudder Valve from the intake/EGR assembly and cleaning that with some degreaser and a wire brush. Else if it looks free of obstructions, you need to do some more digging. I would then like to check for propper operation of the valve, by getting a buddy to start the car and then turn it off. Upon stopping the car, the valve should close and hold close for a few seconds before opening up again. If that doesnt work then you need to diagnose further into the electrical aspects.
of course before you start any of this i am assuming you have checked for obvious flaws like a loose connection or broken wires.