Initial Inspection and Diagnostic Overview

1. Visually inspect catalyst and exhaust system components and related controls that may affect exhaust gas quality or cause backfire or loss of power. Check for:

^ Misrouted, damaged wiring.
^ Damaged coil, distributor, or spark plugs.
^ Corroded, loose connectors.
^ Leaking fuel injectors.
^ Damaged air inlet passages.
^ Inoperative EGR valve.
^ Exhaust pipe pinched, crushed.
^ Damaged, loose vacuum hoses.
^ Incorrect idle speed.
^ Dirty air filter.
^ Damaged catalytic converter.

2. Exercise wiring and connectors for solenoids and other components for obvious problems due to looseness, corrosion, or other damage. Do this when the engine is fully warmed up.
3. Check vacuum lines and connections for looseness, pinching, leakage, splitting, blockage, or other damage that may cause malfunction.
4. If a vacuum line or orifice (restrictor) blockage is suspected as the cause of a malfunction, make corrections before proceeding to the next step.
5. Check engine oil for fuel dilution.
6. If all checks are OK, proceed to Pinpoint Tests.
7. If the symptom is "Fails Emission Test," proceed to Pinpoint Test EG1. If the symptom is "Backfires" or "Lacks Power," proceed to Pinpoint Test EX1.

NOTE: Failure to conform to the Federal Clean Air Act legal requirements for a particular vehicle and calibration is usually the result of one or more emission related system or component malfunctions.