My experience in the "jerky" motion with the cruise engaged is maybe not quite so severe, but it sounds the same. maybe every 2 seconds so I think you still may have a bad rebuild. Good luck.

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Christopher Henkel
1990 190E 2.6 - Arctic white SOLD
1986 190E-16v - Blauswartze
1993 300CE - SOLD
2003 W208 CLK 320 Cabriolet - Magma Red