Hi all my turbo seems to be playing up, when I first got the car in April the boost gauge would not climb higher than 1/4 of the gauge as never drove one before I assumed the norm, then a month ago it was like the car just woke up !! It slung me into the seat and the gauge was at 3/4. And now back to boring 1/4 . Would anyone know what this could be. Please help as don't want to take it to the garage to get ripped off.

Kyle