not drove my cossie for 3 weeks as the diff went, got a diff put it on and alls well, but for some reason my cossie is boosting at 25psi, ive not touched the turbo or anything just the diff, any1 got any solutions. is my turbo fooked

at the mo its stage one and did run 15/16psi, and now as soon as it hits 25 its not getting the fuel it needs as its only running on yellows!!