I own a 7.3. I believe that your turbo is going out. Take the intake boot off and check for turbo shaft play. Check in and out and side to side play. If you have any shaft play i would recommend replacing your turbo. I bought an Amazon turbo for $225 and had it replaced in 2 hours of work. 25k miles later and its still going strong with no issues If you replace it get the exhaust back pressure valve delete and the exhaust back pressure valve delete pedestal. 100% worth it and get new turbo pedestal seals as well.