Few things to check, and they all relate to the PCM controlling the turbo.
The brass nipple on the passenger side of the intake manifold, has a small rubber hose that goes off towards the heater core box. That hose goes to the MAP sensor. Take the hose off and visually check it for cracking, and any restrictions. Check the nipple on the intake. Take an allenwrench (or something else that can't de dropped into the intake) and poke the hole to make sure it is open.
Next is the EGR valve (if you have not deleted your egr cooler).
Pull it out of the intake and clean it <link
Then, check/clean the EP sensor.
Located on the drivers side of your truck, under the degas bottle, sitting on top of a stainless steel tube, attached to the valve cover where the front FICM bracket is. Use two wrenches. One on the tube, on on the sensor and remove it. Clean with carb cleaner, use tie-wire and stick it down into the tube. You can't hurt anything inside the tube, it just goes down to the exhaust manifold. Make sure it is open.
Give all of that a shot and see if this has an effect. Won't cost much beyond your time.