[Wizard]

The main problem you have is in the cruise itself. The cruise unit consists of a couple pulleys that attach to a servo motor. Often, with age, these pulleys get gummed up with dirt, etc. This causes the cruise to react too slowly to maintain slow, steady control. Kinda like a sticking throttle. You have to push extra hard to get it to budge, then it moves too far, etc.

You have 2 options:

Remove the cover and using brake cleaner, etc to clean the pulleys and the cables. Then relube with some white lithium grease, etc.

Buy a cruise eliminator cable.

Wiz