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 battery. Charge or replace as necessary. Refer to DIAGNOSIS AND TESTING .
	2. Corroded or loose battery connections	2. Clean and tighten battery connections. Refer to CLEANING .
	3. Faulty engine starting system	3. Diagnose engine starting system. Refer to DIAGNOSIS AND TESTING .
	4. Faulty coil(s) or control unit	4. Replace ignition coil. Refer to COIL, IGNITION, REMOVAL .
	5. Incorrect spark plug gap	5. Set gap. Refer to SPARK PLUG .
	6. Incorrect cam timing	6. Verify cam timing. Refer to ENGINE/VALVE TIMING - STANDARD PROCEDURE .
	7. Contamination in fuel system	7. Clean fuel system and replace fuel filter.
	8. Faulty fuel pump or wiring	8. Repair or replace as necessary.
	9. Faulty Camshaft Position (CMP) sensor	9. Replace the Camshaft Position (CMP) sensor. Refer to SENSOR, CAMSHAFT POSITION, REMOVAL .
	10. Faulty Crankshaft Position (CKP) sensor	10. Replace Crankshaft Position (CKP) sensor. Refer to SENSOR, CRANKSHAFT POSITION, REMOVAL .
	11. Insufficient quantity of engine oil in the Variable Valve Actuation Assembly (VVAA) due to: Long term storage Engine not started within the last 30 days Replacement of the VVAA (MultiAir module) Restricted VVAA filter screen	11. Operate the starter to fill the VVAA with oil and enable its operation. CAUTION: Do not exceed 20 seconds of starter operation and allow 60 seconds cool-down between cycles. Check the VVAA oil pressure. Refer to DIAGNOSIS AND TESTING .
ENGINE STALLS OR IDLES ROUGH	1. Idle speed too low.	1. Test minimum air flow. (Refer to Appropriate Diagnostic Information)
	2. Incorrect fuel mixture.	2. (Refer to Appropriate Diagnostic Information)
	3. Faulty ignition coil(s).	3. Replace ignition coil. Refer to COIL, IGNITION, REMOVAL .
	4. Incorrect cam timing	4. Verify cam timing. Refer to VALVE TIMING - STANDARD PROCEDURE .
	5. Vacuum leak	5. Inspect intake manifold, manifold gasket, and vacuum hoses.
	6. Faulty Crankshaft Position (CKP) sensor	6. Replace the CKP sensor. Refer to SENSOR, CRANKSHAFT POSITION, REMOVAL .
	7. Contamination in Oil Control Valve (OCV). ECK Only	7. Remove OCV and inspect for contamination. Replace OCV if contaminated. ECK Only
ENGINE LOSS OF POWER	1. Dirty or incorrectly gapped plugs.	1. Correct as necessary. Refer to SPARK PLUG, REMOVAL .
	2. Contamination in fuel system.	2. Clean system and replace fuel filter.
	3. Faulty fuel pump.	3. Test and replace the fuel pump. Refer to MODULE, FUEL PUMP, REMOVAL .
	4. Incorrect valve timing.	4. Correct valve timing.
	5. Leaking cylinder head gasket.	5. Replace cylinder head gasket. Refer to REMOVAL .
	6. Low compression.	6. Determine the cause and repair as necessary. Refer to DIAGNOSIS AND TESTING .
	7. Burned, warped, or pitted valves.	7. Replace valves as necessary. Refer to REMOVAL .
	8. Plugged or restricted exhaust system.	8. Perform exhaust restriction test. Install new parts, as necessary. Refer to RESTRICTION CHECK .
	9. Faulty ignition coil(s).	9. Test and replace ignition coil. Refer to COIL, IGNITION, REMOVAL .
ENGINE MISSES ON ACCELERATION	1. Dirty or incorrectly gapped spark plugs.	1. Clean spark plugs and set gap. Refer to SPARK PLUG, REMOVAL .
	2. Contamination in Fuel System.	2. Clean fuel system and replace fuel filter.
	3. Burned, warped, or pitted valves.	3. Replace valves as necessary. Refer to REMOVAL .
	4. Faulty ignition coil(s).	4. Test and replace ignition coil. Refer to COIL, IGNITION, REMOVAL .
ENGINE MISSES AT HIGH SPEED	1. Dirty or incorrect spark plug gap.	1. Correct as necessary. Refer to SPARK PLUG, REMOVAL .
	2. Faulty ignition coil(s).	2. Test and replace ignition coil. Refer to COIL, IGNITION, REMOVAL .
	3. Contamination in fuel system.	3. Clean system and replace fuel filter.
	4. Dirty fuel injector(s).	4. Test and replace as necessary. (Refer to the Appropriate Diagnostic Information)