Deceleration Fuel-Cut System: Operation
On carbureted models, the system consists of a fuel-cut solenoid, vacuum switch, computer, and connecting tubing and wiring. A slow speed circuit in the carburetor operates except during prolonged periods of deceleration at high engine speeds. Under these conditions, a vacuum switch or computer turns off the fuel-cut solenoid valve creating a lean mixture.
On EFI models, the system consist of the ECU and throttle position sensor. The ECU adjusts the fuel injection duration depending on engine RPM.