2003 Subaru Forester Power/Turbo issue

Hi Guys

I have a 2003 Subaru forester xt 2,0 . When the air around and the car is really cool like in the mornings or at night, the cars turbo has very nice pull and can even bring the traction control light on while turning onto a road with foot flat. My problem is that as soon as the car gets warm or hot that pull disappears. Starts to run like a 2.0 litre none turbo. What could be causing this to happen? Is it a hole in a pipe, is it the intercooler not working properly when the vehicle get hot or is the turbo breaking?

One other thing. When the rpm gets over about 3 000 rmp some times I can hear a constant quick ticking sound. I'm not sure if the engine is supposed to make that sound but I have noticed that its there some times and not there other times.