Mixture Control (Duty) Solenoid
WARNING: This page is about a different car, the 1993 Isuzu Pickup and 1993 Isuzu Amigo. However, it is still accessible from the selected car via links, so may be relevant.
Measure resistance between duty solenoid connector terminals. See Fig 1 . Resistance should be 34.7-46.9 ohms at 68°F (20°C). If resistance is not within specification, replace duty solenoid.