Start with basics such as cold tire pressures, tires and start checking. It of course could be ball joints but it could also be a number of items.

As Larry Bible likes to say: push, pull, prod each wheel.

A bad tie rod end could easily contribute to that vaque feeling. Tip: If one componet is failing often another is also or close to failing.

Haasman

__________________
'03 E320 Wagon-Sold
'95 E320 Wagon-Went to Ex
'93 190E 2.6-Wrecked
'91 300E-Went to Ex
'65 911 Coupe (#302580)