Cruise control engages properly and controls work fine from the signal lever (acceleration, etc.) as it should but it cannot maintain the engaged speed and every 2 seconds, the car accelerates to reach the set speed regardless of the set speed between 25 to 75 mph I tested on the road.

So back in the garage, I raised it on the jacks to see what happens w/ it and tested it again: The vacuum lines are fine. Servo diaphragm depresses inwards as I set it at a certain speed but it looks like it cannot hold the vacuum and starts releasing the cable, causing the speed to drop below the set speed and the accelerator engages again to bring it up to the set speed. This cycle goes on and on every 2 seconds. No other symptoms are present and the car runs fine.

Can I safely assume that the servo diaphragm is leaking, OR, can this symptom may be caused by a problem in the transducer assembly or any part of it?

Thanks in advance...