Fuel System Checks
WARNING: This page is about a different car, the 2003 Chevrolet Cavalier. However, it is still accessible from the selected car via links, so may be relevant.
- Check for a lean or rich engine condition. Using a scan tool observe the oxygen sensor output while operating the vehicle under the symptom condition.
- Check for proper fuel system pressures. See FUEL SYSTEM DIAGNOSIS (CNG) under FUEL SYSTEMS in BASIC DIAGNOSTIC PROCEDURES - 2.2L ALERO, CAVALIER, GRAND AM & SUNFIRE article.
- Check for proper operation of the CNG fuel injectors. See FUEL INJECTOR COIL TEST , FUEL INJECTOR BALANCE TEST WITH SPECIAL TOOL and FUEL INJECTOR BALANCE TEST WITH TECH 2 under FUEL SYSTEMS (CNG) in SYSTEM & COMPONENT TESTS - 2.2L ALERO, CAVALIER, GRAND AM & SUNFIRE article.
- Ensure that the manual shut-off valve is fully open.
- Check for restricted HPR or in-line filters.