My Sportage last month started exhibiting the same sort of symptoms. The engine light came on and suddenly the car had absolutely no pep at all, I would need a good length just to get up to standard travelling speed. Was excruciatingly awful to deal with. Turns out, like others have reported, there was a TSB issued for the Optima's that wasn't issued for the Sportage as well, so my dealership had no ideas at first. Fortunately they identified the problem, and the car seems to be working again so far.
I don't think they had to replace any rods or anything, I just think they had to reflash the ECU correctly to control the wastegate properly.
regardless, it's fixed for now.
2011 Sportage SX AWD w/ NAV - Clear White
2014 Rondo EX - Newport Blue