My Tucson was idling rough intermittently. It actually stalled a couple of times in stop and go traffic. I thought it was the plugs since I was doing oil changes and filter changes by the severe schedule. I replaced the plugs at 28K because I do a lot of low speed driving in heavy traffic. It didn't make a difference. Im now beginning to believe it's the PCV valve not operating correctly even though I get no codes or lights. I was taking it to an oil change place fire the first 20k miles until I noticed that the invoice said they were putting in 5W20 which is too lite for the turbo engine. Im thinking that the thinner oil was allowing more blow by gases into crank case which gummed up the pcv valve prematurely(haven't checked it yet). I've ordered one in the meantime because I figure I might as well replace it since I'm taking it out anyways and they are relatively cheap. Car also has 39K miles on it. Just wondering if this makes sense to the more seasoned mechanics on this site. Anyways I will update thread after changing it.