if it turns out to be the turbo, changing it out turbo is about a one hour job on your truck.
Jack up rightside, remove tire/wheel, remove inner fender (6? screws), spray the four mounting bolts down with Kroil or some other penetrating spray, remove intake boot, remove intercooler hose, remove exhaust band clamp add heat to the four bolts and remove. reverse to install, note do not tighten the four bolts until you have the exhaust band clamp installed and lightly tightened!
Also pick up some Never-Seez High Temperature Stainless Anti Seize NSS-160 for use on the turbo mounting bolts. you might want to change out all of the hoses when you do this.
Don