ours was jerky until i took off the cluster cover, disconnected it, wiped
the grease the DPO put on there to cure the jerky speedo, and made sure it
was clean and installed tightly.  hasn't stuck or jerked since.

bill
currently suffering from hot vanagon syndrome,
the subject of a later post.
'87 syncro westfalia
http://www.scruznet.com/~kasper/pics/westy/