ring break in time

Rapid Vibration at Idle

it-Racing-Vacuum-Gauge-Vibration-at-Idle-1024x1024.png(Image/OnAllCylinders)
If the needle vibrates rapidly between 14 and 20 inches of mercury, but then steadies as rpm increases, you may be dealing with worn valve guides. How fast the needle vibrates is telling of how many valve guides may be worn. (Like all of them!!!)