2000 Ford Focus Speedo falls to Zero while driving

Shakes or Wobbles problem
2000 Ford Focus Manual

Hi I wonder if you can help, my car has recently started this problem. I am driving doesn't matter what speed can be 30mph or 70mph and all of a sudden the speedo drops to zero and there is a slight pull back. When the speedo starts woking again I feel a slight pull and then the car goes along fine. Also no milage is added when the speedo is on zero.
Sometimes when the speedo is at zero and I slow down and go into say 2nd gear the engine stalls. This happened a couple of weeks ago and seems to be happening more regular.

Please help. Thank you