[tinkering]

Could this somehow relate to my problem?

I am having an idle speed problem. It is idling high, causing it to clunk hard into reverse and forward. It is shifting hard too in certain conditions.
This seems to have come around after I replaced the temperature sending unit for the dash gauge. The dash gauge needle never comes right up to ride in the middle or normal running position. I noticed the sending unit connector has two or three wires on it. Could it be that the computer is keeping a high idle while waiting for the operating temperature signal (which never comes)??

I changed out the thermostat, hoping that would bring the gauge up but to no avail.