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 DIAGNOSIS AND TESTING . The following procedures can assist in achieving the proper engine diagnosis.

1. Test cranking amperage draw. See STARTING & CHARGING SYSTEM article.
2. Check intake manifold bolt torque. See INTAKE MANIFOLD .
3. Perform cylinder compression test. See CYLINDER COMPRESSION PRESSURE .
4. Clean or replace spark plugs as necessary.
5. Test coil output voltage and primary resistance. See BASIC DIAGNOSTIC PROCEDURES article. Replace parts as necessary.
6. Test fuel pump for pressure. See BASIC DIAGNOSTIC PROCEDURES article.
7. The air filter elements should be replaced as specified.
8. Inspect crankcase ventilation system.
9. Road test vehicle as a final test.