It looks as if there is a vacuum line that is connected to the cooling lines that run behind the intake plenum. It looks like the spigot on the right side of the engine(sitting in the driver's seat) connects to the erg solenoid, but I'm not sure. And same for the other side. I'm not sure where those lines are supposed to be plugged in. And another question. Do companies make aftermarket intakes for the z31? Even though it has the air flow sensor towards the front of the motor? Thanks.