With these cables you can't replace just the middle you have to replace the
housing and everything.  There are two cables an upper and a lower.  The upper
goes from the speedo to the oxygen sensor box and the lower goes from the box
to the center of the driver's side wheel.  Take off your hubcap and take a
look at the center of the wheel on the driver's side.  There should be a small
clip on the end of a square piece of plastic that protrudes from the wheel's
center.  If this clip is missing and the square piece is pushed back into the
wheel this could cause your problem.  If this isn't it the problem then find
out which speedo cable you need and I will be glad to give you a price on one
with a lifetime warranty.
Ken Wilford
Van-Again
John 3:16