Temp gauge dropping on boost

Ive noticed an odd problem when driving today, when I give it some the coolant temperature gauge goes mad, it will jump about like crazy and drop to the bottom when on boost but as soon as you let off it goes back to the normal position   

What do you think could be causing this? The car never over heats or anything, the temp gauge is just going a bit nutts when I give it some   

Maybe its a bad earth mate ....

I'm thinking it must be an electrical fault of some sort to make it act like that lol

Yep seen this a few times sure the cure is to change the gauge in the clocks or check connection

As long as its no major issue then I don't mind it too much for the time being, I was just worried when I saw it drop because obviously temperature should stay pretty consistent

Check the terminal on the sender unit mate, mine did the same and I found that the terminal was loose, I just soldered it up and it's been ok ever since.  

Do the fans kick in?