I have a 1997 F-250 7.3 Powerstroke with around 223K miles, which was stolen from my stepdad a few years back, got it back all beat up in a ditch, got it running again. We've been using it normally for about a year now. 5 days ago I removed the exhaust so it has the downpipe coming down from the turbo then nothing else, and it ran good and sounded better (in my opinion). Well today I was driving it and I noticed a significant loss in power. The turbo was hardly building any boost. It would usually run around 5-10 driving normal without a load, and 15 when I get on it. Today the most I got out of it was 8 PSI.... RPM's are all where they should be, I didn't here any turbo whistle even at around 3000 rpm. It sounds as if there is no turbo at all, yet when in Neutral/Park, it will whistle no problem like it has with the exhaust off. We never did anything to the turbo itself after getting it back. My stepdad said it never was as powerful/fast as it was before it was stolen. I'm going to reconnect the exhaust and check the turbines to make sure they aren't stuck to the turbo housing and to check for any play. Any tips???