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.

Check the Evaporative Emission (EVAP) control system. See EVAPORATIVE EMISSION CONTROL SYSTEM DIAGNOSIS under EMISSION SYSTEMS & SUB-SYSTEMS in SYSTEM in SYSTEM & COMPONENT TESTING - 1.8L VIBE article.
Check the fuel injectors for leaking. See FUEL INJECTOR BALANCE TEST WITH SPECIAL TOOL under FUEL SYSTEMS in SYSTEM & COMPONENT TESTING - 1.8L VIBE article.