[Roland07]

This may be nothing, but my car (07 Dura 2.0) just started doing it, and it freaks me out a bit.

I'll start it on a cold day, drive a couple miles, and the temp needle makes it to the middle of the gauge.

At the first stop light I come to, while I'm idling, the temp drops back down to the far left.

...that should never happen, right? Do I need to check out my thermostat or something?

 

[felixthecat]

Just a one time thing? Or happens a few times? Hows the coolant?

 

[Roland07]

I notice it every once in a while. It's only on very cold days, and my coolant level is good.

 

[spacemanspif]

If you have a laser thermometer, shoot it at your recovery tank or radiator hose to see what temp your coolant is running. The gauge on my 07 is more idiot light than gauge basically only reading cold - normal - overheating, so if your t-stat is stuck open, you might be bordering on the threshold between cold and normal. Any OBDII reader that can read live data should be able to show you what the coolant temp sensor is reading. If you don't have one, and have a non-apple smart phone, you can download the "torque app" and buy a ~$10 bluetooth dongle that will read your computer info.

It could also be that your heater and blower are set on max and the heater is cooling your engine enough to bring down the temp. If it's only on really cold days and only early in the trip, I'm guessing this is the cause.

 

[Fierceintent]

This happened to my SVT for about a month until it threw a code. Basically it was the thermostat.