8V92 that has started to loose boost. Max I now develop before a shift is about 7 or 8 pounds. Best I can do is 12 pounds locked in a lower gear at 2100 RPM. Changed filters (air and fuel)and tried a new sensor. Good fuel pressure and little black smoke, but no boost. I am seeing soot from around both exhaust manifolds, so guessing the gaskets are gone. Could this be the problem? Turbo turns freely and no DDEC codes indicating a problem. Florida Detroit has ordered manifolds but I'm questioning if this will solve my boost issue.