this has been going on for awhile, at first i thought it was my driveshaft but i was told no

when i'm driving and i'm about 3.5 - 4k RPM i get lots of vibrations. when i floor it i notice it before i shift, and when i'm cruising at about 100 - 110 i can feel it as well. its an oscolating vibration, with a period of prolly about a second or so.

the vibration is not around when i rev it in neutural, only while driving... and i don't think its the driveshaft becasue its RPM dependant not speed dependant.

what might cuase this?

 

First, it is not a very good idea to hit 4k RPM with no load on the engine. That can cauase serious problems, just ask the board member that hit 5K and now has a rod knock. Second, check the tranny mount. That could be bad and cause a vibration. Also, check the u-joints for any play. The easiest way to do this is to get the car on some ramps or jack it up, put on the e-brake, and put the car in neutral. Once that is done, twist, shack, push and pull the driveshaft at each end and listen and feel for any play in it.

 

the tranny mount is polly, would that cause an Oscillating vibration at about 4k RPM's?

 

bump for the night crowd