Diagnostic Aids
WARNING: This page is about a different car, the 2000 Isuzu Rodeo and 2000 Isuzu Amigo. However, it is still accessible from the selected car via links, so may be relevant.
Check for excessive deposits on EGR valve pintle or pintle seat, or deposits that would prevent pintle from extending completely or cause the pintle to stick. Check for damage to wiring harness. While observing scan tool display for EGR position, perform a "wiggle test" of related wiring. A change in displayed value should indicate approximate location of fault.