Engine Performance Diagnostic Table
WARNING: This page is about a different variant/trim than selected.
| CONDITION | POSSIBLE CAUSE | CORRECTION |
|---|---|---|
| ENGINE WILL NOT START | 1. Weak battery. | 1. Test the battery. Charge or replace as necessary. Refer to BATTERY, DIAGNOSIS AND TESTING . |
| 2. Corroded or loose battery connections. | 2. Clean and tighten the battery connections. Apply a coat of light mineral grease to the terminals. Refer to TORQUE SPECIFICATIONS . | |
| 3. Faulty engine starting system. | 3. Test the starting system. Refer to DRIVEABILITY, NON-DTC BASED DIAGNOSTICS . | |
| 4. Faulty coil(s). | 4. Test the ignition coil and replace as needed. Refer to DRIVEABILITY, NON-DTC BASED DIAGNOSTICS . | |
| 5. Incorrect spark plug gap. | 5. Check the spark plug gap. Refer to SPARK PLUG SPECIFICATIONS . | |
| 6. Contamination in fuel system. | 6. Clean the fuel system and replace the fuel filter. Refer to MODULE, FUEL PUMP, REMOVAL and MODULE, FUEL PUMP, INSTALLATION . | |
| 7. Faulty fuel pump. | 7. Test the fuel pump and replace as needed. Refer to DRIVEABILITY, NON-DTC BASED DIAGNOSTICS . | |
| 8. Incorrect cam timing. | 8. Verify cam timing. Refer to VALVE TIMING VERIFICATION . | |
| 9. Faulty Camshaft Position (CMP) sensor. | 9. Replace the Camshaft Position (CMP) sensor. Refer to SENSOR, CAMSHAFT POSITION, REMOVAL and SENSOR, CAMSHAFT POSITION, INSTALLATION . | |
| 10. Faulty Crankshaft Position (CKP) sensor. | 10. Replace the Crankshaft Position (CKP) sensor. Refer to SENSOR, CRANKSHAFT POSITION, REMOVAL and SENSOR, CRANKSHAFT POSITION, INSTALLATION . | |
| ENGINE STALLS OR IDLES ROUGH | 1. Idle speed too low. | 1. Check for Diagnostic Trouble Codes (DTC). Refer to DTC INDEX (1 OF 2) and/or DTC INDEX (2 OF 2) . |
| 2. Incorrect fuel mixture. | 2. Check for Diagnostic Trouble Codes (DTC). Refer to DTC INDEX (1 OF 2) and/or DTC INDEX (2 OF 2) . | |
| 3. Vacuum leak. | 3. Inspect intake manifold, manifold gasket, and vacuum hoses. | |
| 4. Faulty ignition coil(s). | 4. Test and replace the ignition coil. Refer to COIL, IGNITION, REMOVAL and COIL, IGNITION, INSTALLATION . | |
| 5. Faulty Crankshaft Position (CKP) sensor. | 5. Replace the Crankshaft Position (CKP) sensor. Refer to SENSOR, CRANKSHAFT POSITION, REMOVAL and SENSOR, CRANKSHAFT POSITION, INSTALLATION . | |
| 6. Incorrect cam timing. | 6. Verify cam timing. Refer to VALVE TIMING VERIFICATION . | |
| ENGINE LOSS OF POWER | 1. Dirty or incorrectly gapped spark plugs. | 1. Correct as necessary. Refer to SPARK PLUG, REMOVAL and SPARK PLUG, INSTALLATION . |
| 2. Contamination in fuel system. | 2. Clean the fuel system and replace the fuel filter. Refer to MODULE, FUEL PUMP, REMOVAL and MODULE, FUEL PUMP, INSTALLATION . | |
| 3. Faulty fuel pump. | 3. Test and replace the fuel pump. Refer to MODULE, FUEL PUMP, REMOVAL and MODULE, FUEL PUMP, INSTALLATION . | |
| 4. Leaking cylinder head gasket. | 4. Replace the cylinder head gasket. Refer to CYLINDER HEAD, REMOVAL and CYLINDER HEAD, INSTALLATION . | |
| 5. Low compression. | 5. Determine the cause and repair as necessary. Refer to CYLINDER COMPRESSION TEST . | |
| 6. Burned, warped, or pitted valves. | 6. Replace valves as necessary. Refer to VALVES, INTAKE AND EXHAUST, REMOVAL and VALVES, INTAKE AND EXHAUST, INSTALLATION . | |
| 7. Plugged or restricted exhaust system. | 7. Perform the exhaust restriction test. Install new parts as necessary. Refer to RESTRICTION CHECK . | |
| 8. Faulty ignition coil(s). | 8. Test and replace the ignition coil. Refer to COIL, IGNITION, REMOVAL and COIL, IGNITION, INSTALLATION . | |
| 9. Incorrect valve timing. | 9. Verify cam timing. Refer to VALVE TIMING VERIFICATION . | |
| ENGINE MISSES ON ACCELERATION | 1. Dirty or incorrectly gapped spark plugs. | 1. Correct as necessary. Refer to SPARK PLUG, REMOVAL and SPARK PLUG, INSTALLATION . |
| 2. Contamination in fuel system. | 2. Clean fuel system and replace the fuel filter. Refer to MODULE, FUEL PUMP, REMOVAL and MODULE, FUEL PUMP, INSTALLATION . | |
| 3. Burned, warped, or pitted valves. | 3. Replace valves as necessary. Refer to VALVES, INTAKE AND EXHAUST, REMOVAL and VALVES, INTAKE AND EXHAUST, INSTALLATION . | |
| 4. Faulty ignition coil(s). | 4. Test and replace the ignition coil. Refer to COIL, IGNITION, REMOVAL and COIL, IGNITION, INSTALLATION . | |
| ENGINE MISSES AT HIGH SPEED | 1. Dirty or incorrect spark plug gap. | 1. Correct as necessary. Refer to SPARK PLUG, REMOVAL and SPARK PLUG, INSTALLATION . |
| 2. Faulty ignition coil(s). | 2. Test and replace the ignition coil. Refer to COIL, IGNITION, REMOVAL and COIL, IGNITION, INSTALLATION . | |
| 3. Contamination in fuel system. | 3. Clean the fuel system and replace the fuel filter. Refer to MODULE, FUEL PUMP, REMOVAL and MODULE, FUEL PUMP, INSTALLATION . | |
| 4. Dirty fuel injector(s). | 4. Test and replace as necessary. Refer to CHECKING THE FUEL DELIVERY SYSTEM (HARD START) . |