7.3L Powerstrokes from the year 2000 came with faulty turbo bolts that would eventually come loose. Ford issued a Technical Service Bulletin (TSB) that replaces the bolts with new ones and locktight free-of-charge. Make sure to ask your dealer about it if you have a 2000 Ford with a 7.3L and don't know if your turbo bolts have been replaced or not.