Subaru Impreza 2002 Service Manual page 235

MECHANICAL
Trouble
10. Excessive fuel consump-
tion
ENGINE TROUBLE IN GENERAL
Problem Parts, etc.
• Engine control system <Ref. to EN(TURBO)-2, Basic Diagnostic Procedure.>
• Intake system
• Belt
• Compression
• Lubrication system
• Cooling system
• Others
ME(STi)-96
Possible Cause
• Dirty air cleaner element
• Defective timing
• Incorrect valve clearance
• Loosened spark plugs or defective gasket
• Loosened cylinder head bolts or defective gasket
• Improper valve seating
• Defective valve stem
• Worn or broken valve spring
• Worn or stuck piston rings, cylinder and piston
• Incorrect valve timing
• Incorrect oil pressure
• Over cooling
• Accelerator cable out of adjustment
Rank
A
A
B
B
C
C
B
C
C
B
B
C
C
B