I just recently bought a 2002 wrx with a vf48 turbo swap. The problem is a lot of jolting or stuttering when I get past 10psi. The gauge goes from 10 to 15 very rapidly back and fourth. Pulls fine in first all the way but the other gears on have to keep it under 10psi. The last owner claims its the cold weather but I'm not sure. Need some help, its not fin to drive under 10psi!