I did a coolant change few days ago with new toyota SLL coolant. Today i noticed something new which I never experienced before. Temp gauge was at usual just below the half way mark. I accelerated quickly for a few seconds after which i quickly glanced at the temp gauge and noticed it actually went down a little and then after 10 or so seconds it went back to the normal below the half way mark.

Never experienced this before. Has anyone experienced such a thing?

 

I wouldn't be too worry about it. The radiator might got a rush of fresh air and cooled down a little bit.
I would be more worry if the temperature is higher than before since it means you might have some air bubbles in the coolant system.

 

Thats actually what your car is supposed to do, it mean the coolant is flowing well and lowering engine temperature. If you use aftermarket low temp thermostats, it becomes more noticeable. You should only worry if your gauge gets hotter/goes up instead of going down. You can never be too cool... PUN INTENDED!

 

I'd blurp the system to remove any air bubbles.