Diagnosis & Testing: Testing: Notes

The steps listed in the following charts will provide a systematic evaluation of each component that could cause the indicated trouble code or malfunction. After completing a repair, repeat the test to ensure the malfunction has been eliminated.

If after completing any test procedure and the problem persists, other engine associated systems that can affect air/fuel mixture, combustion efficiency or exhaust gas composition may be causing the fault. These systems include:

• Basic carburetor adjustments.
• Mechanical engine operation (plugs, valves, rings).
• Ignition system.
• Intake manifold, carburetor or base plate gaskets.
• Loose vacuum hoses or fittings.