i have great vacuume 20ins. And i was woundering if i had a bad cylinder or something in that matter,change in that vacume reading???? there is funny vidration about 2300 and i can figure it out??? i did compression test on three rotaions i get 170psi and on 5 i get 190psi. The car has 114000 not too many miles but make wounder sometimes.

 

If you had a bad cylinder, the needle on a vacuum gauge would flutter while watching it at idle. 20" is good idle vacuum.