Haha.... I know edy... Start engine n pull spark plug 1 by 1. Since u mentioned abt plug 4. Hehe, call ur mechanic to test wet n dry compression test. Then u know what I mean....
Installed HKS twin plate (GD pro) recently. Got the ice cream sound when holding the clutch which is norm, but will there be any sound (for example, very soft "eeeee") sound when the car is idle and not holding...