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. Charge or replace as necessary.
	2. Corroded or loose battery connections.	2. Clean and tighten battery connections. Apply a coat of light mineral grease to the terminals.
	3. Faulty starter.	3. Refer to Electrical - Engine Systems/Starting - Diagnosis and Testing .
	4. Faulty coil or control unit.	4. Refer to Electrical - Ignition Control/Ignition Control/COIL, Ignition - Removal .
	5. Incorrect spark plug gap.	5. Correct as necessary.
	6. Incorrect right bank cam timing.	6. Refer to COVER(S), Engine Timing .
	7. Dirt or water in fuel system.	7. Clean system and replace fuel filter.
	8. Faulty fuel pump, relay or wiring.	8. Repair or replace as necessary.
	9. Faulty cam or crank sensor	9. Refer to SWITCH, IGNITION .
ENGINE STALLS OR ROUGH IDLE	1. Vacuum leak.	1. Inspect intake manifold and vacuum hoses, repair or replace as necessary.
	2. Faulty crank position sensor	2. Replace crank position sensor
	3. Faulty coil.	3. Refer to Electrical - Ignition Control/Ignition Control/COIL, Ignition - Removal .
	4. Incorrect cam timing.	4. See Engine/Valve Timing - Standard Procedure .
ENGINE LOSS OF POWER	1. Dirty or incorrectly gapped spark plugs.	1. Correct as necessary.
	2. Dirt or water in fuel system.	2. Clean system and replace fuel filter.
	3. Faulty fuel pump.	3. Refer to Fuel System/Fuel Delivery/MODULE, Fuel Pump - Removal .
	4. Blown cylinder head gasket.	4. Replace cylinder head gasket.
	5. Low compression.	5. See CYLINDER COMPRESSION PRESSURE LEAKAGE , repair as necessary.
	6. Burned, warped or pitted valves.	6. Replace as necessary.
	7. Plugged or restricted exhaust system.	7. Inspect and replace as necessary.
	8. Faulty coil.	8. Refer to Electrical - Ignition Control/Ignition Control/COIL, Ignition - Removal .
	9. Incorrect cam timing.	9. Refer to COVER(S), Engine Timing .
ENGINE MISSES ON ACCELERATION	1. Spark plugs dirty or incorrectly gapped.	1. Correct as necessary.
	2. Dirt in fuel system.	2. Clean fuel system.
	3. Burned, warped or pitted valves.	3. Replace as necessary.
	4. Faulty coil.	4. Refer to Electrical - Ignition Control/Ignition Control/COIL, Ignition - Removal .
ENGINE MISSES AT HIGH SPEED	1. Spark plugs dirty or incorrectly gapped.	1. Correct as necessary.
	2. Faulty coil.	2. Refer to Electrical - Ignition Control/Ignition Control/COIL, Ignition - Removal .
	3. Dirt or water in fuel system.	3. Clean system and replace fuel filter.