Symptom Chart: Notes

Condition	Possible Sources	Action
Difficult starting	Damaged ignition system.	Refer to INTAKE AIR, FUEL CHARGING, STARTING AND ENGINE ELECTRONICS - 4.0L SOHC or INTAKE AIR, FUEL CHARGING, STARTING AND ENGINE ELECTRONICS -4.6L (2V) for the procedure. REFER to INTRODUCTION - CNG, FLEX-FUEL & GASOLINE .
	Damaged fuel system.	Refer to INTAKE AIR, FUEL CHARGING, STARTING AND ENGINE ELECTRONICS - 4.0L SOHC or INTAKE AIR, FUEL CHARGING, STARTING AND ENGINE ELECTRONICS -4.6L (2V) for the procedure. REFER to INTRODUCTION - CNG, FLEX-FUEL & GASOLINE .
	Damaged starting system.	Refer to INTAKE AIR, FUEL CHARGING, STARTING AND ENGINE ELECTRONICS - 4.0L SOHC or INTAKE AIR, FUEL CHARGING, STARTING AND ENGINE ELECTRONICS -4.6L (2V) for the procedure. REFER to INTRODUCTION - CNG, FLEX-FUEL & GASOLINE .
	Damaged charging system/battery.	REFER to BATTERY & CHARGING SYSTEM .
	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.	For 4.0L engines, INSTALL a new short block. For 4.6L engines, INSTALL new piston rings.
	Worn cylinder.	For 4.0L engines, INSTALL a new short block. For 4.6L engines, 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 - CNG, FLEX-FUEL & GASOLINE .
Poor idling	Vacuum leaks.	Refer to INTAKE AIR, FUEL CHARGING, STARTING AND ENGINE ELECTRONICS - 4.0L SOHC or INTAKE AIR, FUEL CHARGING, STARTING AND ENGINE ELECTRONICS -4.6L (2V) for the procedure. REFER to INTRODUCTION - CNG, FLEX-FUEL & GASOLINE .
	Malfunctioning or damaged ignition system.	Refer to INTAKE AIR, FUEL CHARGING, STARTING AND ENGINE ELECTRONICS - 4.0L SOHC or INTAKE AIR, FUEL CHARGING, STARTING AND ENGINE ELECTRONICS -4.6L (2V) for the procedure. REFER to INTRODUCTION - CNG, FLEX-FUEL & GASOLINE .
	Malfunctioning or damaged fuel system.	Refer to INTAKE AIR, FUEL CHARGING, STARTING AND ENGINE ELECTRONICS - 4.0L SOHC or INTAKE AIR, FUEL CHARGING, STARTING AND ENGINE ELECTRONICS -4.6L (2V) for the procedure. REFER to INTRODUCTION - CNG, FLEX-FUEL & GASOLINE .
	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 INTAKE AIR, FUEL CHARGING, STARTING AND ENGINE ELECTRONICS - 4.0L SOHC or INTAKE AIR, FUEL CHARGING, STARTING AND ENGINE ELECTRONICS -4.6L (2V) for the procedure. REFER to INTRODUCTION - CNG, FLEX-FUEL & GASOLINE .
	Malfunctioning or damaged ignition system.	Refer to INTAKE AIR, FUEL CHARGING, STARTING AND ENGINE ELECTRONICS - 4.0L SOHC or INTAKE AIR, FUEL CHARGING, STARTING AND ENGINE ELECTRONICS -4.6L (2V) for the procedure. REFER to INTRODUCTION - CNG, FLEX-FUEL & GASOLINE .
	Malfunctioning or damaged air intake system.	Refer to INTAKE AIR, FUEL CHARGING, STARTING AND ENGINE ELECTRONICS - 4.0L SOHC or INTAKE AIR, FUEL CHARGING, STARTING AND ENGINE ELECTRONICS -4.6L (2V) for the procedure. REFER to INTRODUCTION - CNG, FLEX-FUEL & GASOLINE .
	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.	For 4.0L engine, INSTALL a new short block. For 4.6L engine, REPAIR or INSTALL a new piston or cylinder block.
Engine noise	Leaking exhaust system.	REPAIR exhaust leakage.
	Incorrect drive belt tension.	REFER to SPECIFICATIONS & DRIVE BELT ROUTING .
	Malfunctioning generator bearing.	Refer to BATTERY & CHARGING SYSTEM for the procedure.
	Malfunctioning water pump bearing.	REFER to ENGINE COOLING .
	Malfunctioning or damaged cooling system.	REFER to ENGINE COOLING .
	Malfunctioning or damaged fuel system.	Refer to INTAKE AIR, FUEL CHARGING, STARTING AND ENGINE ELECTRONICS - 4.0L SOHC or INTAKE AIR, FUEL CHARGING, STARTING AND ENGINE ELECTRONICS -4.6L (2V) for the procedure. REFER to INTRODUCTION - CNG, FLEX-FUEL & GASOLINE .
	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. For 4.0L engines, INSTALL a new short block. For 4.6L engines, ADJUST clearance or INSTALL a new crankshaft main bearing.
	Seized or heat-damaged crankshaft main bearing.	For 4.0L engines, INSTALL a new short block. For 4.6L engines, INSTALL a new crankshaft main bearing.
	Excessive crankshaft end play.	INSTALL a new thrust bearing or crankshaft.
	Excessive connecting rod bearing clearance.	For 4.0L engines, INSTALL a new short block. For 4.6L engines, INSTALL a new connecting rod bearing or connecting rod.
	Heat damaged connecting rod bearing.	For 4.0L engine, INSTALL a new short block. For 4.6L engine, INSTALL a new connecting rod bearing.
	Damaged connecting rod bushing.	For 4.0L engine, INSTALL a new short block. For 4.6L engine, INSTALL a new connecting rod bushing.
	Worn cylinder.	For 4.0L engine, INSTALL a new short block. For 4.6L engine, REPAIR or INSTALL a new cylinder block.
	Worn piston or piston pin.	For 4.0L engine, INSTALL a new short block. For 4.6L engine, INSTALL a new piston or piston pin.
	Damaged piston rings.	For 4.0L engine, INSTALL a new short block. For 4.6L engine, INSTALL new piston rings.
	Bent connecting rod.	For 4.0L engine, INSTALL a new short block. For 4.6L engine, 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 INTAKE AIR, FUEL CHARGING, STARTING AND ENGINE ELECTRONICS - 4.0L SOHC or INTAKE AIR, FUEL CHARGING, STARTING AND ENGINE ELECTRONICS -4.6L (2V) for the procedure. REFER to INTRODUCTION - CNG, FLEX-FUEL & GASOLINE .
	Malfunctioning or damaged fuel system.	Refer to INTAKE AIR, FUEL CHARGING, STARTING AND ENGINE ELECTRONICS - 4.0L SOHC or INTAKE AIR, FUEL CHARGING, STARTING AND ENGINE ELECTRONICS -4.6L (2V) for the procedure. REFER to INTRODUCTION - CNG, FLEX-FUEL & GASOLINE .
	Malfunctioning or damaged air intake system.	Refer to INTAKE AIR, FUEL CHARGING, STARTING AND ENGINE ELECTRONICS - 4.0L SOHC or INTAKE AIR, FUEL CHARGING, STARTING AND ENGINE ELECTRONICS -4.6L (2V) for the procedure. REFER to INTRODUCTION - CNG, FLEX-FUEL & GASOLINE .
	Damaged or plugged exhaust system.	INSPECT exhaust system.
	Incorrect tire size.	REFER to SUSPENSION SYSTEM .
	Dragging brakes.	REFER to BRAKE SYSTEM .
	Slipping transmission.	Refer to AUTOMATIC TRANSMISSION - 5R55S for the procedure.
	Malfunctioning valve tappet or lash adjuster.	INSTALL a new valve tappet or lash adjuster.
	Damaged valve tappet guide or valve tappet.	For 4.0L engines, INSTALL a new cylinder head. For 4.6L engines, INSTALL a new valve tappet guide or valve tappet.
	Compression leakage at valve seat.	For 4.0L engines, INSTALL a new cylinder head. For 4.6L engines, REPAIR or INSTALL a new valve, valve seat or cylinder head.
	Seized valve stem.	For 4.0L engines, INSTALL a new cylinder head. For 4.6L engines, INSTALL a new valve.
	Weak or broken valve spring.	INSTALL a new valve spring.
	Worn or damaged camshaft.	For 4.0L engines, INSTALL a new cylinder head. For 4.6L engines, INSTALL a new camshaft.
	Damaged head gasket.	INSTALL a new head gasket.
	Cracked or distorted cylinder head.	For 4.0L engines, INSTALL a new short block. For 4.6L engines, INSTALL a new cylinder head.
	Damaged, worn or sticking piston ring (s).	For 4.0L engines, INSTALL a new short block. For 4.6L engines, REPAIR or INSTALL a new piston ring(s).
	Worn or damaged piston.	For 4.0L engines, INSTALL a new short block. For 4.6L engines, INSTALL a new piston and piston pin.