Check for any split, disconnected or perforated vacuum hoses. Also, check PCV valve for proper operation.
Remove the positive crankcase ventilation valve.
Insert a thin stick into the positive crankcase ventilation valve from the threaded side to check that the plunger moves.
If the plunger does not move,the positive crankcase ventilation valve is clogged. Clean or replace it.
Are vacuum hoses and PCV OK?
YES
Go to "Spark Plug Inspection"
NO
Replace faulty vacuum hoses or PCV
Repair as necessary and go to "Verification of Vehicle Repair" procedure
Check the following items below for spark plug.
Remove spark plugs and check gap and plug condition.
Check the electrode condition(wear or carbon deposit)
Check the insulators condition(crack,etc)
Check the carbon deposit
Specification: gap : 1.0~1.1mm
Are spark plugs gapped properly and in good condition?
YES
Go to "Fuel injector Inspection"
NO
Faulty spark plugs
Repair as necessary and go to "Verification of Vehicle Repair"
Check for fuel injector operation.
Are fuel injectors working normally and dispensing proper volume?
YES
Temporarily install a known good HO2S and check for proper operation.
if problem is corrected, replace HO2S.
NO
Repair as necessary and go to "Verification of Vehicle Repair" procedure.