Engine Performance

It is important that the vehicle is operating to its optimum performance level to maintain fuel economy and the lowest emission levels. If vehicle is not operating to these standards, refer to Engine Diagnosis. The following procedures can assist in achieving the proper engine diagnosis.
1. Test cranking amperage draw. Refer to Starting and Charging.
2. Check intake manifold bolt torque; Refer to Engine, Intake Manifold.
3. Perform cylinder compression test. Refer to Cylinder Compression Pressure Test.
4. Clean or replace spark plugs as necessary and adjust gap as specified in Powertrain Management. Tighten to specifications.
5. Test resistance of spark plug cables. Refer to Powertrain Management.
6. Inspect the primary wires. Test coil output voltage and primary resistance. Replace parts as necessary.
7. Test fuel pump for pressure. Refer Powertrain Management.
8. The air filter elements should be replaced as specified in Maintenance.
9. Inspect crankcase ventilation system. For emission controls see Powertrain Management for service procedures.
10. Road test vehicle as a final test.