Possible Causes & Corrections

Check for the following:

• Check PCM grounds. Ensure they are clean, tight and properly located.
• Check for poor quality or alcohol contaminated fuel.
• Check canister purge system (staying on).
• Check for fuel in pressure regulator vacuum hose. If fuel is present, replace regulator.
• Check fuel system for incorrect fuel pressure. See BASIC FUEL SYSTEM CHECKS in appropriate BASIC DIAGNOSTIC PROCEDURES article.
• Check fuel injectors. Perform injector balance test. See FUEL INJECTOR BALANCE TEST under FUEL SYSTEMS in appropriate SYSTEM & COMPONENT TESTING article.
• Check injector harness locations. Ensure injectors are connected to correct injector/cylinder according to firing order.