My 95 850 Turbo (102K miles) is having a strange fast vibration on the freeway. Just cruising along barely noticable (or gone), foot off the gas vibration is gone, BUT step on the gas and the vibration gets bad (its a fast vibration not a tire). I had the tires replaced and its still there! It doesn't do it on side streets or 45mph roads, I've just noticed it on the freeway so far. This is my first front wheel drive car, I've only had rear wheel drive sports cars and4x4's in the past, but it feels a lot like the universal going badon a rear wheel drive vehicle. I'm thinking its one of the half shaft/drive shafts going, but does this sound like the correct symptom? I also have a creaking or knocking in what sounds like the top part of the drivers side strut, but I'm not sure if thats a related issue or something different (my sports cars and 4x4's didnt have struts). Any ideas or pointers to look for?

Thanks

 

vibration could be the engine mounts. The top mount and front engine mount come to mind as culprits. Knocking from front suspension could be the spring seats.

 

I hadexactly the same symptom with my car two years ago- turned out to be the engine mounts - but I did suspect the drive shafts - it was vibrating badly (with awful noise - no shake through the steering though)in between deceleration and acceleration, and all the time at certain higher speeds(70+). The problem was not detectable below 50. The top engine mount I understand is quite weak on the 850 and will need replacement at some point. The knocking sound you describe I also experience on my car, and have been told by my mechanic that it is the spring seat.

 

Those would have been my guesses also. I've done the motor mounts ontwo of my 850's. I'm getting ready to do the spring seats and strut caps on the V70.

 

I'll crawl under it this weekend and check the engine mounts. I'm guessing that if they are bad it will be obvious by looking at them right?
Are the spring seats on the struts something that will eventually fail, or will they keep knocking around? I'd like to wait for warmer weather for those if I can.