Wow, an 03 with only 30K on it? Cherry
Well, at least the guage is not going the other way

.
First thought that comes to mind is the temp sending unit. That would be my first suggestion of things to check.
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AKA..dingdong
Silver 03 Taco Limited TRD 4dr. 4X4 V6 Auto
Extang Tonneau, LineX Liner, 3" Toytec lift with front diff drop, rear Alcan, AAL's w/ degree shims, Procomp shocks front and rear, Locker mod, 285/75/16 Nitto's, Code alarm/remote start CA670, Putco Stainless Grill, Several CUSTOM off road pin stripes