please explain what you mean by turbo farts lol. need a little more information on this. any smoke white/black? does the low power issue seem to be worse at low speed or highway speed? normally if say it has low power on takeoff but better at highway speeds (or the other way around) that usually means turbo sticking. usually cleaning the turbo only works for a short time as it is almost impossible to remove all the corrosion from around the vanes. on first impression i think you are right about the turbo needing to be replaced. but depending on whether or not it is smoking excessively that could also be injector issues as these engines are prone to failing injectors especially at high mileage. which usually mean low power and not necessarily a misfire.