I have a vibration that has me confused. It seems to happen as the motor is decelerating between 2500rpms and 1500 rpms. Sometimes pulling the clutch in makes it go away sometimes it doesn't. If it is happening during acceleration it is not very pronounced. It does not happen while cruising. The internals of the motor are stock. I did here a metal on metal knock today after start up. Was random and went away quickly. Where should I start looking so we can figure this out together?