I am the proud father of a 93' Na 2+2. I have a problem with my Z completely shutting down when I slow from speeds ranging from 45 - 60. This happens on hills and also on flat road. I first gained this problem when my water pump was failing but now that a new one is installed I am still experiencing the problem. I have asked around and can find no answers or even reasonable guesses. I would greatly appreciate the help. Thanks