What have you done, suspension-wise, in the last two years? 150K miles is a lot for the car.
Simple tests to check for suspension parts.
Raise the front of the vehicle. It is kind of hard for me to explain the details, so I will use analogy where I can. Imagine the tire is a giant compass. You will have top (North), bottom (South), right (East) and left (West).
Check the rubber boot on the ball joint, if it is torn, replace the boot.
With your hands, grab top and bottom of the tire, rock it back and forth, towards the top and bottom. You should not be able to move it more than 1/4 of an inch. If you can move more than 1/4 inch, replace ball joint.
Tie rod end:
With your hands, grab left and right of the tire, rock it back and forth, towards the left and right. You should not be able to move it more than 1/4 of an inch. If you can move more than 1/4 inch, replace outer tie rod end. If it doesn't move past 1/4 inch, but there is so much play, replace inner tie rod end. If you have both movement, replace both tie rod ends.
Most technicians push the edge of the vehicle. If the vehicle bounces more than once, replace the strut on that corner. I do that, but I also have another test for you to do. Have someone follow you driving at 55 - 65 mph on a straight highway. The he observes that your car moves up and down more than once, then you need to replace your struts.
Based on your description "like the whole body losing its grip on my tires", I believe that you need struts replaced. But it doesn't hurt to check all the other suspension parts, as well.
Let us know.
Saturday, December 20th, 2008 AT 12:30 AM