and what does it do?

http://cgi.ebay.com/ebaymotors/ws/eB...ERC_BidConfirm

 

Steering stabilizer is a shock absorber for the steering linkage. IT mounts to the frame or other solid non-moving point on one side and to the steering linkage on the other. It takes the harsh inputs from potholes and road irregularities out of the steering system so the wheel is not jerked out of your hands while driving.

 

how long or at what interval should these be replaced? I live in nyc and I thought it was normal when hitting a pothole for your steeringwheel to shake.

 

I don't really know if there is a recommended interval. I've never replaced one on my cars because I usually trade them with less than 40,000 miles. It is probably a very simple and inexpensive bolt on item that can be changed in the garage.