New to the site, having a problem with my wifes car, while getting on to the freeway and going full throttle or even while going freeway speed and then stepping on it to pass someone there is a severe front end shake that is felt throughout the car including in the steering wheel. But as soon as I let out of the throttle it goes away regardless of how fast I am going. My first thought was wheel out of balance or bad tire but it seems like you should notice it regardless of being in the throttle or not. I dont seem to notice it while driving around in the city and taking off from a stop I dont notice it either. Any help would be greatly appreciated. Thanks in advance

 

So I just put the car in the air and while searching around underneath for anything that was loose I noticed that the passenger side inner cv boot is totally ripped and grease is everywhere, could this possibly be what is causing my shake? I know I need to repair this regardless but just hoping this solves my front end problem.

 

Chances are that half shaft is whats giving you problems. Replace it ASAP then go from there.

 

My 2000 S40 had some moderate shake at about 160k miles that got worse and worse over time. It ended up being the front, passenger side axle that needed to be replaced. And the job was not cheap. Hope this isn't what ends up being your problem.