Excessive Exhaust Emissions/Odors

Definition: Vehicle fails an emission test. Vehicle has excessive "rotten egg" smell. Excessive odors do not necessarily indicate excessive emissions.
POSSIBLE CAUSE ACTION
Incorrect idle speed Check idle speed adjustments, refer to ADJUSTMENT PROCEDURES

Fuel in crankcase Determine cause (flooding, excessive cranking etc.)
Change oil and filter

Fuel metering Check air/fuel ratio (02 sensor voltage), refer to COMPUTERIZED ENGINE CONTROLS
Perform injector service (cleaning), refer to MAINTENANCE PROCEDURES
Check fuel pressure (check return hose), refer to FUEL SYSTEM DIAGNOSIS

Faulty fuel cap Replace fuel cap

Lead contamination of catalytic converter Check for missing fill pipe restrictor
Replace catalytic converter

Poor or contaminated fuel Check for excessive alcohol content
Recommend higher grade fuel
Drain fuel tank and add clean fuel