I've been having an issue with blue smoke from idle to about 1800 rpms. 2003 7.3 with 166,000 miles dp tuner DIY intake and 4 inch straight pipe. This winter I noticed that if I didn't plug my truck in or if I let it sit for a couple days it would idle really rough like it was missin until it warmed up. About 2500 miles ago I tried some of that hot shot oil additive and after that the blue smoke started and I still have the rough idle. It runs great at and above 2000 rpm. So I'm thinking maybe injector o-rings but not sure. I don't get black smoke anymore just blue and I've had to add about a gallon of oil since I put that additive in. Any help would be greatly appreciated.