Noticed a weird vibration while crusing above 65. The vibrations aren't constant they come and go in a pattern of every three seconds. The car shakes violently and it can't be the ball joints since I just changed them. It all started after I changed my driver side ocv filter. Another thing is that I hear the same pattern when the car is at idle. What on earth could this be????

 

You are comparing two very different vibrations. One is a suspension vibration and the other is an engine vibration. Which one is it?

You started by saying the vibration comes and goes with speed. But then you mentioned vibration at idle and that would suggest rpm range.

 

I meant that the idle vibration pattern is similiar to the vibration pattern while cruising about 65 mph except while cruising above 65 the vibration is more violent. Its vibrates hard for about 3 seconds at a time. I figured maybe they were connected. The suspension is fine, even got the suspension checked by a mechanic so that's ruled out.

 

Motor/tranny mounts? 100-150,000 I believe is the expected lifetime of these