Symptom Chart

SYMPTOM CHART

Condition	Possible Sources	Action
Difficult starting	Damaged ignition system. Damaged fuel system. Damaged starting system.	Refer to appropriate article for the procedure. REFER to INTRODUCTION - GASOLINE article.
	Damaged charging system/battery.	REFER to CHARGING SYSTEM - GENERAL INFORMATION .
	Burnt valve.	INSTALL a new valve.
	Worn piston.	For 4.0L engines, INSTALL a new piston and connecting rod assembly. For 4.6L engines, INSTALL a new piston.
	Worn piston rings.	INSTALL new piston rings.
	Worn cylinder.	REPAIR or INSTALL a new cylinder block.
	Damaged head gasket.	INSTALL a new head gasket.
	Damaged cooling system.	Refer to ENGINE COOLING for the procedure. REFER to INTRODUCTION - GASOLINE article.
Poor idling	Vacuum leaks.	Refer to the appropriate article for the procedure. REFER to INTRODUCTION - GASOLINE article.
	Malfunctioning or damaged ignition system.
	Malfunctioning or damaged fuel system.
	Damaged valve tappet or lash adjuster.	INSTALL a new valve tappet or lash adjuster.
	Damaged valve tappet guide or lash adjuster.	INSTALL a new valve tappet guide or valve tappet.
	Incorrect valve-to-valve seat contact.	REPAIR or INSTALL a new valve or valve seat.
	Damaged head gasket.	INSTALL a new head gasket.
	Worn or damaged engine support brackets.	INSTALL a new engine support brackets.
	Worn or damaged engine support insulators.	INSTALL a new engine support insulator.
	Worn or damaged transmission insulator and retainer.	INSTALL a new transmission insulator and retainer.
Abnormal combustion	Malfunctioning or damaged fuel system.	Refer to the appropriate article for the procedure. REFER to INTRODUCTION - GASOLINE article.
	Malfunctioning or damaged ignition system.
	Malfunctioning or damaged air intake system.
	Damaged valve tappet or lash adjuster.	INSTALL a new valve tappet or lash adjuster.
	Damaged valve tappet guide or valve tappet.	INSTALL a new valve tappet guide or valve tappet.
	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.	For 4.0L engines, INSTALL a new piston and connecting rod assembly. For 4.6L engine, REPAIR or INSTALL new piston rings.
	Worn piston ring groove.	For 4.0L engine, INSTALL a new piston and connecting rod assembly. For 4.6L engine, INSTALL a new piston and piston pin.
	Worn piston or cylinder.	REPAIR or INSTALL a new piston or cylinder block.
Engine noise	Leaking exhaust system.	REPAIR exhaust leakage.
	Incorrect drive belt tension.	REFER to ACCESSORY DRIVE .
	Malfunctioning generator bearing.	Refer to GENERATOR AND REGULATOR for the procedure.
	Malfunctioning coolant pump bearing.	REFER to ENGINE COOLING .
	Malfunctioning or damaged cooling system.
	Malfunctioning or damaged fuel system.	Refer to FUEL TANK & LINES for the procedure. REFER to INTRODUCTION - GASOLINE 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.	CAUTION: Remove the cylinder heads before removing the crankshaft. Failure to do so can result in engine damage. ADJUST clearance or INSTALL new crankshaft main bearings.
	Seized or heat-damaged crankshaft main bearing.	INSTALL new crankshaft main bearings.
	Excessive crankshaft end play.	INSTALL a new thrust bearing or crankshaft.
	Excessive connecting rod bearing clearance.	INSTALL new connecting rod bearings or connecting rods.
	Heat damaged connecting rod bearing.	INSTALL new connecting rod bearings.
	Damaged 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 valve tappet or lash adjuster.	INSTALL a new valve tappet or lash adjuster.
	Excessive valve tappet or lash adjuster clearance.	ADJUST clearance or INSTALL a new valve tappet guide or valve tappet.
	Broken valve spring.	INSTALL a new valve spring.
	Excessive valve guide clearance.	ADJUST clearance or INSTALL a new valve guide or valve.
Insufficient power	Malfunctioning or damaged ignition system.	Refer to ENGINE IGNITION - 4.0L SOHC or ENGINE IGNITION - 4.6L (3V) for the procedure. REFER to INTRODUCTION - GASOLINE article.
	Electronic throttle control (ETC) system concerns.
	Malfunctioning or damaged fuel system.
	Malfunctioning or damaged air intake system.
	Damaged or plugged exhaust system.	INSPECT exhaust system.
	Incorrect tire size.	REFER to SUSPENSION SYSTEM-GENERAL INFORMATION .
	Dragging brakes.	REFER to BRAKE SYSTEM-GENERAL INFORMATION .
	Slipping transmission.	Refer to AUTOMATIC TRANSAXLE/TRANSMISSION for the procedure.
	Malfunctioning valve tappet or lash adjuster.	INSTALL a new valve tappet or lash adjuster.
	Damaged valve tappet guide or valve tappet.	INSTALL a new valve tappet guide or valve tappet.
	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.