Diagnostic Aids
WARNING: This page is about a different car, the 2000 Isuzu Hombre. However, it is still accessible from the selected car via links, so may be relevant.
Never solder HO2S wires. Check for HO2S contamination and correct installation. Check for split, missing or disconnected vacuum hoses. Inspect exhaust system for damage. Check all wiring connections and condition of harness.