i have a 92 f250 with a n/a 7.3 idi...tach isnt working and it wont shift properly. already replaced the tach sensor and need to know what else it could be your help is much apreciated as this is my DD

 

have you flushed your tranny fluid? maybe replaced the filter? the fluid could just be gunking things up down there.. that happened to me, after a flush and new filter the tranny shifted fine... as far as the tach, hope someone else will chime in on that one.. good luck bud!!