I have a 2004 F350 6.0 and I recently am having a bit of trouble with it. Truck has 409,xxx KM (254,xxx miles) and is bone stock. About a month or so ago out of nowhere the truck seemed a little sluggish at times. I then noticed in my passenger mirror, when the truck seemed sluggish it was pissing out black smoke. I changed out my air filter and fuel filters for OEM replacements, and that half solved my problem. The truck no longer gives out black smoke from the exhaust however it still is sluggish when I get on the throttle at times. The truck now pisses out a blueish smoke when I get on the throttle most times as if its burning oil. I feel as though it may be something to do with my turbo, as every once in a while i step on the gas and it barely accelerates and then goes like hell, similar to a sports car with a small engine/big turbo. I am very new to powerstrokes/diesels so any help would be greatly appreciated.