Fuel System Checks

Check for incorrect fuel pressure. See FUEL SYSTEM DIAGNOSIS under FUEL SYSTEMS in BASIC DIAGNOSTIC PROCEDURES - 2.2L ION article.
Check for a restricted fuel filter. See FUEL SYSTEM DIAGNOSIS under FUEL SYSTEMS in BASIC DIAGNOSTIC PROCEDURES - 2.2L ION article.
Check the fuel injectors. See FUEL INJECTOR BALANCE TEST WITH SPECIAL TOOL and FUEL INJECTOR COIL TEST under FUEL SYSTEMS in SYSTEM & COMPONENT TESTING - 2.2L ION article.
Check for a contaminated fuel condition. 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 - 2.2L ION article.
Check for the following conditions that may cause the engine to run lean:
- Water intrusion in the HO2S connector.
- An exhaust leak between the HO2S and the engine.
- Vacuum leaks.
- Incorrect fuel pressure. See FUEL SYSTEM DIAGNOSIS under FUEL SYSTEMS in BASIC DIAGNOSTIC PROCEDURES - 2.2L ION article.
- Restricted fuel injectors. See FUEL SYSTEM DIAGNOSIS under FUEL SYSTEMS in BASIC DIAGNOSTIC PROCEDURES - 2.2L ION article.
- 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 - 2.2L ION article.
- Vacuum hoses that are split, kinked, or improperly connected.