On my car - a Ford Fiesta - the hydraulic actuator is fitted immediately below the pedal arm - a pin comes from the actuator and rests against the pedal arm. If they get out of line with one another I get the symptoms you describe. A simple clip should hold them in line together but the clip is lost. I have fixed it twice now with a plastic cable tie.
My Fiesta has no cruise control.
Good Luck...
October 2015
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