Fuel System Checks

WARNING: This page is about a different car, the 2003 Pontiac Vibe. However, it is still accessible from the selected car via links, so may be relevant.

Inspect the operation of the fuel system for rich or lean condition. Operate the vehicle under the conditions that caused the concern. Monitor the Fuel Trim parameter on a scan tool in order to identify the problem.
- Lean
  
  The Long Term Fuel Trim will be more than 20 percent. Refer to DIAGNOSTIC AIDS in DTC P0171: FUEL TRIM SYSTEM LEAN under DIAGNOSTIC TESTS in SELF-DIAGNOSTICS - 1.8L VIBE article.
- Rich
  
  The Long Term Fuel Trim will be less than -20 percent. Refer to DIAGNOSTIC AIDS in DTC P0172: FUEL TRIM SYSTEM RICH under DIAGNOSTIC TESTS in SELF-DIAGNOSTICS - 1.8L VIBE article.
Test the fuel pressure while the condition exists. See FUEL SYSTEM DIAGNOSIS under FUEL SYSTEMS in SYSTEM & COMPONENT TESTING - 1.8L VIBE article.
Check Evaporative Emission (EVAP) control system. See ELECTRONIC IGNITION SYSTEM DIAGNOSIS under IGNITION SYSTEMS in SYSTEM & COMPONENT TESTING article.
Test the fuel injectors for leaking. See FUEL INJECTOR BALANCE TEST WITH SPECIAL TOOL under FUEL SYSTEMS in SYSTEM & COMPONENT TESTING - 1.8L VIBE article.