Tahoe surging but not brakes?

[David Smith]

Does it feel like warped rotors? Was it very rusty and or dirty? My bet would be the rotors are not seated properly. Have had this before. Doesn't take much.

I agree. When you are going fast, the rotors are turning much faster and it would be hard to feeling the rocking or pulsing. On the other hand, when you get down to 15 or under, you can probably feel it very well.

My vote is for a rotor issue of some kind. Not seated, warped, etc...

 

[RED TAHOE LS]

Broken belt in a tire. Jack up the vehicle, spin the tires slowly one @ a time, the tread pattern will wobble when you find the correct one or maybe two. Good luck, keep us posted when you find it.
David g.............