Help- my car likes to kind of float around

[Daddythump]

I have a 99 528i and when I go down the freeway my car likes to kind of float around a bit when I get to higher speeds. It feels kind of like when a big semi or burst of wind hits the car and moves you around a bit?

[MIKYZZ4]

I would say your vehicles suspension needs refreshing,
followed by a proper wheel alignment.

I can't tell you what parts specifically to replace,
not without an inspection,
so you have 2 options:
Get your vehicle up on jack stands for a DIY inspection.
or
Get the vehicle up on a lift at your favorite shop for inspection.