S-Type (X200) V8-4.2L (2005)
Variable Induction Control Valve: Description and Operation
Intake Manifold Tuning (IMT) Valve
There are two intake manifold tuning (IMT) valves, an upper and a lower, sometimes referred to as number one and two respectively. They are a two
position (open and close) device used to create a variable air intake system. The IMT valve positions are switched by signals from the ECM to optimize
torque across the engine's speed and load range. On vehicles fitted with a 3.0L engine the upper IMT valve opens between 4,100 and 6,150 rpm while
the lower IMT valve opens between 3,900 and 6,150 rpm.