At this point they are considered incertae sedis;in other words, we know that they are theropods; and probably coelurosaurs; but we don't know who they are related to or how they fit into the big picture of theropod phylogeny.
Idle speed is adjusted by means of the idle control valve, which is a solenoid-operated valve that is generally automatically adjusted by a computer. One problem that can occur with this component is a loss of power (from a severed line or a short) but a more common problem is simply dirt and grime.
ISB Idle Speed Control. All engines spend a significant portion of their life at idle. The ISB engine gives you the ability to set desired idle speed. It also gives you the ability to control idle speed using the Cruise Control switches. Idle Speed Control increases fuel economy and can be helpful in reducing cab noise and vibration. Idle time also affects fuel economy of the vehicle.