PSI output changes time after time
I noticed top boost changes without any reasons. I mean i am living on 770ft above sea level and my area almost flat. Using the same gas all the time. No wastegate mods, nothing made before. Outside temperature did not affect to top boost. Two month ago i have a 19-20 PSI. Then it suddenly changes to 15-16 PSI, ofcourse affecting acceleration. Yesterday i decided to drive around.. and get 19 again!
Any one knows what is going on?