Here is the result I have got 1: 170, 2:160, 3: 165, 4:170 And I also realized there maybe a oil leak inside, say.....when I took out the spark plugs for cylinder 1 and 3, there weren't any oil/ fluid attached to it (Brown in colour) while sparks plugs from cylinder 2 and 4, there were. Now I am reading the manual, and try to identify the problems.... Any brothers got any ideas, welcome to post here... Cheers :)