...and make sure your coolant fill is the rec'd 50-50 coolant
and distilled water.

We have run our '01 3.0 is some serious warm summer temps, in
hours of stop and go driving and the needle has never budged
from straight up, dead center. This isn't Nigeria, I realize, but
something is amiss...if no leaks, the water pump is the obvious
try, imo.
GL,mD

PS: you didn't mention whether or not your aux cooling fan is coming on; it should
on any kind of condition where your engine is warmed up and the ambient temps
are just "warm", imo. Without that aux fan to pull air across the radiator space,
you are fighting an uphill battle to maintain the engine's proper temp.

Oil "cools" the "bottom"/lower end of the engine and the circulating coolant cools
the "top" end of engine, to be poetic...but without the upper cooling, the entire
engine can get past the tipping point of proper operating temps.