Yes Repair or replace oil
intake pipe
12 Check if there is leaking or jam in oil intake
pipe.
No Replace oil pump
Yes Repair or replace oil
return pipe
13 Check if the oil return pipe is bended or
jammed.
No Replace fuel pressure
regulator
Yes Next step 14 Let engine run at idle speed, after coolant
temperature reaches normal value, then use a
diagnostic tester to check if ignition advance
angle is normal.
No Check other systems
Yes Replace the coolant
temperature sensor
15 Pull off the coolant temperature sensor and
observe if the engine is in right conditions.
No Next step
Yes Next step 16 Check if the compression pressure of cylinder is
normal.
No Troubleshooting
Yes Next step 17 Check if resistance value of ignition cable of
each cylinder is normal (can not exceed 16kÙ).
No Replace
Yes Replace 18 Check if ignition coil and ignition cable system
works normally and if crack exists on ignition
coil.
No Next step
Yes Replace ECU 19 Check if the spark plug is in right conditions.
No Replace spark plug
Note: After finish of warming up, engine will enter normal idle speed state, under
which, unsteady revolution is in connection to many factors, such as spark plug, ignition
cable, ignition coil, if air leak exists in the system, if carbon deposit exists in the system
and if cylinder pressure is normal an so forth.
