My 1986 735i has an intermittent cruise control problem. I set the speed at say, 100km/hr, let go of the accelerator pedal and the speed drops 5-10k and them returns to what's set. Then, the car will surge and drop in speed up and down for a few minutes before settling. It is a sensation like a misfire as the tach doesn't jump around and the speedo seems pretty steady. What's up with this? Thanks for any suggestions, Drew.