Symptom Chart - Engine Performance

Condition	Possible Sources	Action
Difficult starting	Inoperative or damaged ignition system Air or vacuum leak Inoperative or damaged fuel system Inoperative or damaged starting system	Refer to the appropriate Engine article for the procedure. REFER to the Introduction - Gasoline Engines article.
	Damaged charging system/battery	REFER to CHARGING SYSTEM - GENERAL INFORMATION article.
	Burnt valve	INSTALL a new valve.
	Worn piston	INSTALL a new piston.
	Worn piston rings	INSTALL new piston rings.
	Worn cylinder	INSTALL a new cylinder block.
	Damaged head gasket	INSTALL a new head gasket.
	Inoperative or damaged cooling system (if equipped, fail-safe cooling invoked)	Refer to the appropriate Engine article for the procedure. REFER to the Introduction - Gasoline Engines article.
Poor idling	Vacuum leaks Inoperative or damaged EGR system	Refer to the appropriate Engine article for the procedure. REFER to the Introduction - Gasoline Engines article.
	Inoperative or damaged ignition system	Refer to the appropriate Engine article for the procedure.
	Inoperative or damaged cooling system (if equipped, fail-safe cooling invoked) Inoperative or damaged fuel system	Refer to the appropriate Engine article for the procedure. REFER to the Introduction - Gasoline Engines article.
	Damaged hydraulic lash adjuster	INSTALL a new hydraulic lash adjuster.
	Incorrect valve-to-valve seat contact	INSTALL a new cylinder head.
	Damaged head gasket	INSTALL a new head gasket.
Abnormal combustion	Inoperative or damaged fuel system Air or vacuum leaks EGR system fault Inoperative or damaged cooling system (if equipped, fail-safe cooling invoked) Inoperative or damaged ignition system	Refer to the appropriate Engine article for the procedure. REFER to the Introduction - Gasoline Engines article.
	Malfunctioning or damaged air intake system	Refer to the appropriate Engine article for the procedure. REFER to the Introduction - Gasoline Engines article.
	Damaged hydraulic lash adjuster	INSTALL a new hydraulic lash adjuster.
	Burnt or sticking valve	REPAIR or INSTALL a new valve.
	Weak or broken valve spring	INSTALL a new valve spring.
	Carbon accumulation in combustion chamber	ELIMINATE carbon buildup.
Excessive oil consumption	Leaking oil	REPAIR oil leakage.
	Malfunctioning PCV system	REPAIR or INSTALL new necessary components.
	Worn valve stem seal	INSTALL a new valve stem seal.
	Worn valve stem or valve guide	INSTALL a new valve and valve guide.
	Sticking piston rings	REPAIR or INSTALL new piston rings.
	Worn piston ring groove	INSTALL a new piston and piston pin.
	Worn piston or cylinder	INSTALL a new piston or cylinder block.
Engine noise	Leaking exhaust system	REPAIR exhaust leakage.
	Incorrect drive belt tension	REFER to ACCESSORY DRIVE article.
	Malfunctioning generator bearing	Refer to the appropriate Battery and Charging System article for the procedure.
	Malfunctioning water pump bearing	REFER to ENGINE COOLING article.
	Malfunctioning or damaged cooling system	REFER to ENGINE COOLING article.
	Malfunctioning or damaged fuel system	Refer to the appropriate Engine article for the procedure. REFER to the Introduction - Gasoline Engines article.
	Loose timing chain/belt	ADJUST or INSTALL a new timing chain/belt.
	Damaged timing chain tensioner	INSTALL a new timing chain tensioner.
	Excessive main bearing clearance	NOTE: Remove the cylinder heads before removing the crankshaft. Failure to do so can result in engine damage. INSTALL a new crankshaft main bearing.
	Seized or heat damaged crankshaft main bearing	INSTALL a new crankshaft main bearing.
	Excessive crankshaft end play	INSTALL a new thrust bearing or crankshaft.
	Excessive connecting rod bearing clearance	INSTALL a new connecting rod bearing or connecting rod.
	Heat damaged connecting rod bearing	INSTALL a new connecting rod bearing.
	Damaged connecting rod bushing	INSTALL a new connecting rod bushing.
	Worn cylinder	REPAIR or INSTALL a new cylinder block.
	Worn piston or piston pin	INSTALL a new piston or piston pin.
	Damaged piston rings	INSTALL new piston rings.
	Bent connecting rod	INSTALL a new connecting rod.
	Malfunctioning hydraulic lash adjuster	INSTALL a new hydraulic lash adjuster.
	Broken valve spring	INSTALL a new valve spring.
	Excessive valve guide clearance	ADJUST clearance or INSTALL a new valve guide or valve.
Insufficient power	Inoperative or damaged ignition system Air intake system blockage Lubrication system blockage Inoperative or damaged fuel system	Refer to the appropriate Engine article for the procedure. REFER to the Introduction - Gasoline Engines article.
	Oil level too high	DRAIN oil to correct level.
	Incorrect engine oil	INSTALL correct specification engine oil.
	Excessive accessory drive belt loading Inoperative or damaged cooling system (if equipped, fail-safe cooling invoked)	Refer to the appropriate Engine article for the procedure. REFER to the Introduction - Gasoline Engines article.
	Damaged or plugged exhaust system	INSPECT exhaust system.
	Incorrect tire size	REFER to SUSPENSION SYSTEM - GENERAL INFORMATION article.
	Dragging brakes	REFER to BRAKE SYSTEM - GENERAL INFORMATION article.
	Slipping transmission	Refer to the appropriate Automatic Transmission article for the procedure.
	Malfunctioning hydraulic lash adjuster	INSTALL a new hydraulic lash adjuster.
	Compression leakage at valve seat	REPAIR or INSTALL a new valve, valve seat or cylinder head.
	Seized valve stem	INSTALL a new valve.
	Weak or broken valve spring	INSTALL a new valve spring.
	Worn or damaged camshaft	INSTALL a new camshaft.
	Damaged head gasket	INSTALL a new head gasket.
	Cracked or distorted cylinder head	INSTALL a new cylinder head.
	Damaged, worn or sticking piston ring(s)	REPAIR or INSTALL a new piston ring(s).
	Worn or damaged piston	INSTALL a new piston and piston pin.
Oil in coolant	Leaking head gasket	INSTALL a new head gasket. Refer to the appropriate Engine article for the procedure.
	Leaking oil cooler	INSTALL a new oil cooler. Refer to the appropriate Engine article for the procedure.
	Leaking oil filter adapter	INSTALL a new oil filter adapter. Refer to the appropriate Engine article for the procedure.
	Damaged cylinder head	INSPECT the engine components for damage. INSTALL new components as necessary. Refer to the appropriate Engine article for the procedure.
	Damaged cylinder block	INSPECT the engine components for damage. INSTALL new components as necessary. Refer to the appropriate Engine article for the procedure.
Coolant in oil	Leaking head gasket Leaking oil cooler Leaking oil filter adapter Damaged cylinder head Damaged cylinder block	INSPECT the engine components for damage. INSTALL new components as necessary. Refer to the appropriate Engine article for the procedure.