I am a tech an an independent shop and was given a Sportage with a simular issue. I have had 3 come in with the same problem prevoiusly. A fuel injection cleaning fixed all 3. But the one given to me seems to be stubborn. It was at a previous shop and at the dealr. They replaced the plugs, coils, wires, timing belt, and mass air flow sensor. I cleaned the injectors running 2 cans through and it ran great. After a week of sitting it runs worse than ever. So I pulled the injectors and have sent them out to be flow tested and cleaned. I did ohm them and they were all 16.6 and spec is 13.8. Since they were all the same thet didn't concern me. So I am now waiting to see. You might want to get a fuel injection cleaning most shops charge between $49 and $69 in my area. Like I said it fixed 3 other sportages with the same issue.