Subaru Legacy 2002 Service Manual page 1099

Mechanical
TROUBLE
2. Rough idle and engine
stall
ENGINE TROUBLE IN GENERAL
PROBLEM PARTS, ETC.
¼ Engine control system <Ref. to EN(H6)-2, Basic Diagnostic Procedure.>
¼ Intake system
¼ Fuel line
¼ Chain
¼ Compression
¼ Lubrication system
¼ Cooling system
¼ Others
ME(H6)-78
POSSIBLE CAUSE
¼ Loosened or cracked intake duct
¼ Loosened or cracked PCV hose
¼ Loosened or cracked vacuum hose
¼ Defective intake manifold gasket
¼ Defective throttle body gasket
¼ Defective PCV valve
¼ Loosened oil filter cap
¼ Dirty air cleaner element
¼ Defective fuel pump and relay
¼ Clogged fuel line
¼ Lack of or insufficient fuel
¼ Defective timing
¼ Incorrect valve clearance
¼ Loosened spark plugs or defective gasket
¼ Loosened cylinder head bolts or defective gasket
¼ Improper valve seating
¼ Defective valve stem
¼ Worn or broken valve spring
¼ Worn or stuck piston rings, cylinder and piston
¼ Incorrect valve timing
¼ Improper engine oil (low viscosity)
¼ Incorrect oil pressure
¼ Defective rocker cover gasket
¼ Overheating
¼ Malfunction of evaporative emission control system
¼ Stuck or damaged throttle valve
¼ Accelerator cable out of adjustment
RANK
A
A
A
A
B
B
C
B
C
C
C
B
C
B
B
B
B
C
B
B
A
B
B
C
C
A
B
C