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Diagnosis And Testing: Performance

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CONDITION POSSIBLE CAUSE CORRECTION
ENGINE WILL NOT START 1. Weak battery. 1. Charge or replace as necessary.
2. Corroded or loose battery connections. 2. Clean and tighten the battery connections. Apply a coat of light mineral grease to the terminals.
3. Faulty starter. 3 Diagnose the engine starting system. Refer to DIAGNOSIS AND TESTING - STARTING SYSTEM .
4. Incorrect spark plug gap. 4 Verify the spark plug gap. Refer to SPECIFICATIONS .
5. Dirt or water in the fuel system. 5. Clean the system and replace the fuel filter.
6. Faulty fuel pump, relay or wiring. 6 Diagnose the fuel system wiring. Refer to STANDARD PROCEDURE .
ENGINE STALLS OR ROUGH IDLE 1. Vacuum leak. 1. Inspect the intake manifold and vacuum hoses, repair or replace as necessary.
 
ENGINE LOSS OF POWER 1. Dirty or incorrectly gapped spark plugs. 1. Replace the spark plugs.
2. Dirt or water in fuel system. 2. Clean the system and replace the fuel filter.
3. Blown cylinder head gasket. 3. Replace the cylinder head gasket.
4. Low compression. 4 Test the engine compression. Refer to CYLINDER COMPRESSION TEST  .
5. Burned, warped or pitted valves. 5. Replace as necessary.
6. Plugged or restricted exhaust system. 6. Inspect and replace as necessary.