Engine Performance

It is important that the vehicle is operating to its optimum performance level to maintain fuel economy and the lowest emission levels. The following procedures can assist in achieving the proper engine diagnosis.
1. Test cranking amperage draw. Refer to Starting and Charging.
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. Refer to Powertrain Management.
5. Test resistance of spark plug cables. Refer to Powertrain Management.
6. Test ignition coils primary and secondary resistance. Replace parts as necessary. Refer to Powertrain Management.
7. Test fuel pump for pressure. Refer to Powertrain Management.
8. The air filter elements should be replaced as specified.
9. Inspect crankcase ventilation system. Refer to Powertrain Management.
10. Road test vehicle as a final test.