Fuel System
WARNING: This page is about a different car, the 2003 Oldsmobile Aurora. However, it is still accessible from the selected car via links, so may be relevant.
- Check fuel pressure. See FUEL SYSTEM DIAGNOSIS under FUEL SYSTEM CHECKS in BASIC DIAGNOSTIC PROCEDURES - 4.0L AURORA article.
- Check for fuel contamination. See ALCOHOL/CONTAMINANTS-IN-FUEL DIAGNOSIS WITH SPECIAL TOOL or ALCOHOL/CONTAMINANTS-IN-FUEL DIAGNOSIS WITHOUT SPECIAL TOOL under FUEL SYSTEMS in SYSTEM & COMPONENT TESTING - 4.0L AURORA article.
Check items that can cause an engine to run lean:
- Any water intrusion into the HO2S harness connector.
- An exhaust leak between the HO2S and the engine.
- Any vacuum leaks.
- Incorrect fuel pressure. See FUEL SYSTEM DIAGNOSIS under FUEL SYSTEM CHECKS in BASIC DIAGNOSTIC PROCEDURES - 4.0L AURORA article.
- Any lean fuel injectors. See FUEL SYSTEM DIAGNOSIS under FUEL SYSTEM CHECKS in BASIC DIAGNOSTIC PROCEDURES - 4.0L AURORA article.
- An inaccurate Mass Airflow (MAF) sensor. See PID VALUE CHARTS in PID VOLTAGE CHARTS - AURORA article.
- Vacuum hoses for splits, kinks and proper connections.