So this has been annoying me since day 1...

Some cold starts the temp gauge stays at "cold" and behaves normally. Other times (flip a coin) the gauge will go up to "normal" then over 30 seconds fall back to cold.

The coolant housing was replaced, so it's a new thermostat and ECT sensor. The car does know that the engine is cold, it idles fast and the heat is delayed until the coolant warms up. Either way the gauge acts normally afterward.

Here's video one, regular cold start:
Here's one from today, after sitting 9 hours in < 45F ambient, start it up and it pegs to center, then falls back down.
I guess it's not really worth worrying about since the car starts normally and otherwise behaves fine, but the fact that it does it randomly is what's so annoying to me. What do other people's gauges do? Does it stay at cold, not do this weird halfway point gauge check?

Thanks,
-Michael

 

Get an OBDII reader and monitor the coolant temperature. If the readings follow the gauge, then your ECT sensor or connections to the ECM are acting up, or possibly the ECM itself.

If not, there is a problem in your instrument cluster. You might then try a battery disconnect for 10 seconds or so and see if it resets the computer in the instrument cluster and fixes the problem.