Hi, last few days my coolant temp gage is reading all over the place! Sometimes it shows low, then correct and while showing the correct temp. I replaced the sensor today and it is still acting up?

You said you put a new sender in it - so I believe it will be 1 of 2 things: Either your display or wiring. To test this you need to disconnect the wire and make certain that the display is reading "LO". Next ground the wire to the block or chassis, the display should read "300" now and the red warning should turn on. If you get both you most likely have wire that is nearly split. You may want to examine all connectors and move them around and watch the display.