The most likely suspect is a binding upper strut mount. Reach over the top of one of the front tires and wrap your fingertips around one of the coils of the coil spring. Have a helper slowly turn the steering wheel. You should feel that spring rotate fairly smoothly along with the wheel. If the upper mount is binding, you'll feel the spring wind up and build tension, then suddenly pop free and turn. That popping is most likely what you're feeling.
The strut assembly has to be disassembled to replace the upper mount, then the car must be aligned. Since this repair involves the entire job of taking things apart, you might as well consider having the struts replaced right away. They aren't terribly expensive.
There are other ways those upper mounts can fail but there's no good way to know except to take them apart and inspect them. For that reason it is common to ask to have the struts replaced, and after the mechanic has everything apart, he finds those bad mounts and has to tell you more parts are needed than were expected. We hate having to tell customers they need more things, so to avoid that a lot of mechanics quote repair estimates that already include those mounts, or they sell you the complete new assembly that includes a new spring and mount. Those have only been around a few years, and were developed because of this problem and because while you're paying for more parts, it takes a whole lot less time, so it costs the same in the long run and you have all new parts.
Thursday, September 18th, 2014 AT 8:48 PM