Engine Diagnosis - Performance

WARNING: This page is about a different variant/trim than selected.

CONDITION	POSSIBLE CAUSE	CORRECTION
ENGINE WILL NOT START	1. Weak battery.	1. Test battery. Charge or replace as necessary. Refer to Electrical - Engine Systems/Battery System/BATTERY - Description
	2. Corroded or loose battery connections.	2. Clean and tighten battery connections. Apply a coat of light mineral grease to terminals.
	3. Faulty starter.	3. Test starting system.
	4. Faulty coil(s) or control unit.	4. Test and replace as needed. Refer to Non-DTC Diagnostics/Driveability - Gas - Diagnosis and Testing
	5. Incorrect spark plug gap.	5. Check and adjust gap as needed.
	6. Contamination in fuel system.	6. Clean system and replace fuel filter.
	7. Faulty fuel pump.	7. Test fuel pump and replace as needed. Refer to Non-DTC Diagnostics/Driveability - Gas - Diagnosis and Testing
	8. Incorrect engine timing.	8. Check for a skipped timing chain.
ENGINE STALLS OR IDLES ROUGH	1. Idle speed too low.	1. Test minimum air flow.
	2. Incorrect fuel mixture.	2. Replace fuel.
	3. Intake manifold leakage.	3. Inspect intake manifold gasket, manifold, and vacuum hoses.
	4. Faulty coil(s).	4. Test and replace as necessary. Refer to Non-DTC Diagnostics/Driveability - Gas - Diagnosis and Testing
ENGINE LOSS OF POWER	1. Dirty or incorrectly gapped plugs.	1. Set gap as needed or replace plug(s).
	2. Contamination in fuel system.	2. Clean system and replace fuel filter.
	3. Faulty fuel pump.	3. Test and replace as necessary. Refer to Non-DTC Diagnostics/Driveability - Gas - Diagnosis and Testing
	4. Incorrect valve timing.	4. Correct valve timing as needed.
	5. Leaking cylinder head gasket.	5. Replace cylinder head gasket.
	6. Low compression.	6. Test compression of each cylinder.
	7. Burned, warped, or pitted valves.	7. Replace valves.
	8. Plugged or restricted exhaust system.	8. Check exhaust system restriction. Replace parts, as necessary.
	9. Faulty coil(s).	9. Test and replace as necessary. Refer to Non-DTC Diagnostics/Driveability - Gas - Diagnosis and Testing
ENGINE MISSES ON ACCELERATION	1. Dirty or incorrectly gapped spark plugs.	1. Set gap as needed or replace plug(s).
	2. Contamination in Fuel System.	2. Clean fuel system and replace fuel filter.
	3. Burned, warped, or pitted valves.	3. Replace valves.
	4. Faulty coil(s).	4. Test and replace as necessary. Refer to Non-DTC Diagnostics/Driveability - Gas - Diagnosis and Testing
ENGINE MISSES AT HIGH SPEED	1. Dirty or incorrect spark plug gap.	1. Set gap as needed or replace plug(s).
	2. Faulty coil(s).	2. Test and replace as necessary. Refer to Non-DTC Diagnostics/Driveability - Gas - Diagnosis and Testing
	3. Dirty fuel injector(s).	Test and replace as necessary. Refer to Non-DTC Diagnostics/Driveability - Gas - Diagnosis and Testing
	4. Contamination in fuel system.	4. Clean system and replace fuel filter.