What I am saying is that you cannot get a P0500 code in your car its OBD-1. The only code your car will put out for VSS is 17 on the check engine light
and to remedy it you inspect the vehicle speed sensor output or wiring to it. And furthermore you would be having a permanent check light with a VSS code along with a dead speedometer.
What you had posted was
P0500 code on an OBD-1 car and the mechanic also had a 16 pin to 2 pin convertor to hook up to a switch connector and it pulled error codes onto an OBD-2 reader and he also suggested you to change the distributor.
This whole paragraph is completely stupid. - Its like saying a doctor put a stethescope on your foot to check heartbeat and concluded that you have a case of cold and flu and it would require surgery on your gall bladder. Would you trust such a doctor - I hope not.