Engine Performance

Performance Checks

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 Testing and Inspection, Diagnostic Tables, Engine Diagnosis-Performance.
The following procedures can assist in achieving the proper engine diagnosis.
1. Test cranking amperage draw.
2. Tighten the intake manifold bolts to specifications.
3. Perform cylinder compression test.
4. Clean or replace spark plugs as necessary and adjust gap. Tighten to specifications.
5. Test resistance of spark plug cables.
6. Test ignition coils primary and secondary resistance. Replace parts as necessary.
7. Test fuel pump for pressure.
8. The air filter elements should be replaced if required.
9. Inspect crankcase ventilation system.
10. Road test vehicle as a final test.