Subaru 2009 IMPREZA, Service Manual

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ME(H4DOTC)-104
Engine Trouble in General
MECHANICAL
2. Rough idle and engine
stall Engine control system <Ref. to EN(H4DOTC)(diag)-2, Basic Diagnostic Procedure.> A
Intake system Loosened or cracked intake duct A
Loosened or cracked PCV hose A
Loosened or cracked vacuum hose A
Defective intake manifold gasket B
Defective throttle body gasket B
Defective PCV valve C
Loosened oil filler cap B
Dirty air cleaner element C
Fuel line Defective fuel pump and relay C
Clogged fuel line C
Lack of fuel or insufficient fuel B
Timing belt Defective timing C
Compression Incorrect valve clearance B
Loosened spark plug or defective gasket B
Loosened cylinder head bolt or defective cylinder head
gasket B
Improper valve sealing B
Defective valve stem C
Worn or broken valve spring B
Worn or stuck piston rings, cylinder and piston B
Incorrect valve timing A
Improper engine oil (low viscosity) B
Lubrication system Incorrect oil pressure B
Defective rocker cover gasket C
Cooling system Over-heating C
Others Evaporative emission control system malfunction A
Stuck or damaged throttle valve B
Symptom Problem parts etc. Possible cause RANK