it is the bastard brother of the Idle Air Control Valve. 9 times out of 10 when somebody has a rolling idle everybody cries out IAC when usually its the FITV that has backed off internally. It is located on the bottom of the TB, has two hoses that come out that are connected to coolant lines. You have to pop the top off with two screw that hold it in, and then screw the plastic internal cap all the way back down.