Cruise control speed oscillating

[kaspr]

Hi,

I have a '97 DeVille. When I set the cruise, all functions work, except that it doesn't maintain a constant cruise speed. For example, if I set the cruise at 60, it will coast down to 58, and then accelerate up to 62, and then let up again so that it's just coasting back down to 58, and then over again. So basically, the engine never establishes a steady RPM. It's constantly revving up to accelerate, and then going down close to idle for the coast.

Please let me know what you recommend. Also, I was wondering what exactly does the servo do? Could that be the problem. I don't know much about how cruise's work; never taken one apart before. Any help would be much appreciated, THANKS!

kaspr