IMO, what matters more than anything concerning where the gauge points is (unless it's obviously broken and for example, pegged on hot or bottomed out on cold when it clearly shouldn't be), does the engine warm up to and run at the temp rating of the thermostat. By design, the engine is designed to run at that temp, the PCM ('puter) is therefore counting on and expecting this to happen. The wandering needle, the usual first suspicion on that is low on coolant/air in system. This because, the sender is designed to sample the temp of a liquid, not air.

My 2 cents on the matter.

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2004 Ranger FX4 Level II, 5R55E, Sonic Blue Pearl

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