mine .. consistantly does this as well .. it will go up and down like a yoyo now .. tried the sender , and coolant level , checked wiring ..

I havent fixed it yet , but from what I have found is,

apparently , there are 3 screws that hold the "guage" into the main dash pod . 1 of these is a ground screw , and apparrently over time can loosen . although I have not taken mine apart to repair it , and cant confirm this .. if you have some time , you might just tighten these back up smile and let me know ..

.

86 4x4 , fiberglass bed , 1/2 doors , hood, etc..
84 Custom 2WD 400HP supra suspension , full frame
83 Trekker SR5
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