Temp gauge sluggish/twitchy even with new ground?

[Heavy Armor]

So my temp gauge will gradually creep up to the warm mark, but even on a hot day in the 90's will not climb any higher. It also has a bad habit of wiggling, ticking, and sometimes diving to zero. The old negative wire seemed to have good connection, but just to be safe I replaced it with a brand new ground tied directly to the battery. Made sure the positive terminal was clean. No change, still slow and twitchy. What do you think could be causing this? Just a bad sending unit?

[cushman eagle]

It could be a bad connection anywhere from the sending unit through the harness to the guage.
Do you have a service manual with which you could follow the schematic?
There is a site on this forum from which you can download one if you have non

[GrandpaDenny]

It's in my .sig below