is the truck out of warranty? how many mile are on it? you really cant tell if the turbo is toast until you take it apart. like 03shadowgreygt said check all that stuff first. if the truck is out of warranty you can easily remove the turbo and take it apart. they get alot of rust inside the veins of the turbo and they can be cleaned (ford wants this over replacing them and if you do it yourself its a free repair if you got the time and tools). you would have to replace the turbo tho if the unison ring which the veins sit in is cracked. that unison ring is for that specific turbo and is non serviceable. does it also make a noise when you let off the pedal? does it lag a lot more than it ever did before?