Low power, bad mileage
I have a 2000 f250 with no chip or any after-market additions. A few weeks ago on a road trip with no load it started sounding sputtery when attempting to pass. I noticed that passing power was very lacking. It was slow getting up to speed, even when it downshifted. I also noticed it sucking down the diesel. The next day, after a very cold night in the woods, it took a while to get it to crank and it blew out a big smoke cloud when it finally did. It wouldn't idle without me hitting the throttle. I had to drive it for a couple of miles before it would idle right.
Since then, I can only get about 200-250 miles out of a tank and its sluggish. I don't seem to hear the turbo all the time either, but I know that it is turning.