It means they all do that.

 

Your right, forgot. Funny this Alfa didn't do it until today ..... been watching everything closely since I am doing some major work on the car.

 

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Resurrecting this old thread since I have the same problem (temp gauge reading although the ignition is off & engine is cold).

How did you resolve the problem ?

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Why does this thread says RESOLVED when it's not ?

My guess is that the needle travels (sweeps) a mechanical path of some kind. The point where the needle stays(sticks) when the power is off is because friction has developed in that point of the needle's rotation.

When the power is turned off, the force of gravity acts on the needle to pull it down to its' resting point. Since the mass of the needle is very small this is a small force, nonetheless in absence of any other force it would be enough to do the job. The force resisting the gravitational force is some kind of friction. The force required to overcome the friction in the needle's mechanism is greater than the force of gravity, so the needle stays put.

Either clean or repair the needle mechanism or increase the gravitational force.

Hope this helps.